With horror stories about so-called ‘cowboy’ builders, budgets spiraling out of control and sites being left half-finished, it’s a wonder anyone builds anything! However, we find the vast majority of builders and their sub-contractors to be decent, honest people who take pride in their work, and who will go to great lengths to satisfy their clients and protect their reputation.
“This guide shows you how to choose your main builder/contractor and related sub-contractors like electricians, plumbers, carpenters, joiners, ground workers, bricklayers, plasterers and decorators. ”
The two main sections of this article are:
It is important to be aware that while the construction industry may be regulated in terms of health and safety on-site, and for important structural details, via Building Regulations, there are no minimum standards of training required for many of its workers.
It is rare for safety inspectors to visit domestic jobs except if a notifiable accident has happened. Likewise, a Building Control Officer (BCO) can only ever make strategically limited visits in order to look at certain site stages/conditions when the builder tells him the work is ready to be checked. Typical trigger points might include the points at which:
The foundation trenches are dug and leveled
The concrete poured
Damp proof course fitted
Drains laid and tested
Steel work in place
Anyone can set themselves up as a general builder as long as they deliver the goods. No formal qualifications are necessary. As a result, many “general builders” have no official training behind them, but have instead learnt their skills via experience on-the-tools. .
On the flip side, sub-contractors, particularly electricians and plumbers, are key trades that are highly skilled and regulated. You will need to rely on them for design of mechanical and electricals, heating, hot and cold water elements, and Building Regulations self certification of their work. Therefore, the choice of sub-contractor, their working relationship with both the general builder/main contractor, the design team and you as client, is extremely important to the success of any project.
“Managing and coordinating all of the separate trades on-site takes a great deal of time, experience and ability to lead people. If it goes wrong many clients can end up in a real mess. As such we would always suggest that you target one point of responsibility and hire a single general builder/main contractor, who will then internally employ their own subcontractors/trades under a traditional “Design-Bid-Build” procurement route. This article is written with this in mind. So how do you choose the right people for the job?”
Find the right main contractor for your building project
Your project is only as good as the quality of the workmanship that goes into it, but hiring skilled, passionate tradespeople is not always easy.
We feel you should expect:
A cost effective price
Completion close to the date agreed
An appropriate quality of workmanship
Tidiness
Courtesy
Honesty
Engaging a good contractor for your project may seem like a daunting task, but you can de-stress the process by devoting time to researching the key information you will need in order to find and hire the right people.
What are the requisite skills and formal qualifications they should possess?
Should they belong to any professional or trade bodies?
How relevant is their past practical experience?
What can you expect in terms of design input?
What kind of assumptions can you make in terms of their knowledge of buildings and specifications?
Later on in the article, we go into much more detail, on what we feel are appropriate questions to ask.
“The trick is to sort out the wheat from the chaff. This will take some time and trouble, and you may need to lower your expectations related to cost of work and how quickly your project can be started and finished.”
What is the right kind of main contractor for your project?
A contractor for a multi-unit housing development or luxury block of flats will have to be highly organised, usually with multiple managers, a well-organised back office and teams. Such contractors tend to be expensive, and in most cases, would be over the top for a kitchen extension or loft conversion.
At the other end, there are plenty of small owner/manager builders who do a lot of the on-site work themselves, organising everything from a mobile phone on their hip. With such low overheads, a builder like this should be much cheaper, but the level of service, organisation and speed may not compare.
“You are looking for the most appropriate balance of low price, high quality and good organisation. You never get the best of all three, but at this stage, it’s key to decide what will be the best fit for you. ”
Step 1 — how to look for the right main contractor
As stated previously building work is not licensed in the UK, which means that anybody in this country can call themselves a builder and advertise themselves as such.
The first step to finding a competent, genuinely skilled builder is to make up a list of likely firms and whittle it down by investigation.
“Remember, contractors who are good at what they do, don’t have to advertise. They get much of their work through happy clients recommending them to their friends. Similarly, no good builder is likely to be available quickly.”
1. Check recommendations from Those you know and trust
Asking trusted sources is by far the best way forward. Ask us at Harvey Norman Architects. Also ask friends, family, neighbours, lawyers, estate agents and others who have built projects like the one you propose. Local building suppliers and other trade-related businesses such as project managers, structural engineers or quantity surveyors can offer referrals too.
2. Identify similar local sites
Are there similar, recently completed or ongoing projects under construction in your area? We always think local is best. So, look for site boards by building sites.
3. Note the Signs of good and bad building practice
Once you have identified sites, watch them over a period of time to see if standards are maintained and monitor them for signs of good and bad building practice.
Signs of good building practice and responsible behaviour
A company sign is on display
Vehicles associated with the site are well presented and parked sensibly
On first appearance, the site is clean, tidy and organised
Roads and pavements are not damaged or muddy
Where appropriate, suitable fencing is available
The site facilities are appropriate for the project
Workers appearance is in keeping with a professional outfit
Equipment is clean and in good order
No trailing leads are evident, except in close proximity to the work
Standard of works appears to be good
Workers are polite
Noise levels are acceptable (no loud radios)
Security, and health and safety signs are evident i.e.
Visitors to report to the site office
There are warning signs for pedestrians that construction work is in progress
Standard health and safety signs plainly on view
Workers are wearing appropriate personal protective equipment
Where appropriate, materials are neatly stacked and protected
Signs of bad building practice and irresponsible behavior
Untidy site
Materials poorly stacked and unprotected
General lack of signs
Loud radios
Poor site facilities
Workers not wearing personal protective equipment
Poor standard of work
Signs of burning materials on site
Inadequate security, such as no fences (if appropriate)
4. Check trade associations local lists:
Many general builders/contractors are members of a trade body or guild. In theory membership gives them a degree of integrity, because membership usually requires credit and quality control checks. Some, such as the Federation of Master Builders, offer insurance-backed guarantees, standard contracts and a dispute arbitration process. Some of the main organisations are:
Federation of Master Builders (FMB): FMB is the largest building industry trade body, representing over 13,000 vetted small- and medium-sized builders. There is a code of conduct and it operates a service that will match its members to your needs.
TrustMark: This Government initiative is designed to help the public find reliable contractors and tradespeople. It has a vetting procedure and awards the TrustMark to those that comply with Government-endorsed standards. Search for local members.
National Federation of Builders (NFB): The NFB represents around 2,000 small and medium sized contractors and has a code of conduct and arbitration procedure. You can search online by location and specialism.
The Guild of Master Craftsmen (GMC): The GMC is a trade association that represents a number of different trades. Members are asked to observe a code of conduct and the guild offers a dispute resolution service. Search for a variety of local craftspeople.
5. some other ideas
Local authority planning and building control offices sometimes maintain a list of approved contractors available to the public. We always keep an eye on the contractors nominated for the regional LABC Regional Building Excellence Awards
Note any proactive contractors who contact you after your planning application was submitted
Local construction groups and organisations are a useful resource
Social media may also point you in a direction
Consumer rating websites that list contractors and have feedback from previous customers such as Google, Checkatrade and RatedPeople
A word of warning
None of the ways cited above are 100% reliable in themselves. We always have a degree of scepticism about the reliability of internet reviews and in our experience, some very good smaller general builders do not belong to the trade associations above because of how they perceive the cost versus benefit.
By far the best review is from those you know and trust, but these suggestions should allow you to be able to pull together an initial list of possible local contractors. We suggest you now cut this initial long list down, to get a list of say six contractors to undertake the next stage of detailed due diligence and verification.
Step 2 — Checking out the contractors you have identified
“Start with a company’s website. Review their project pages. The lack of an internet presence says a lot about the contractor too. We like to see professionally presented, open and upfront websites with lots of information about the company such as company and VAT numbers, contact details, office addresses and profiles of the team.”
We also look for what associations/organisations, logos and links the contractor is proud to display on their website. This gives an idea of the firm’s management, culture and level of organisation. Examples might be:
A trade organisation, the CIOB is aimed particularly at higher level education. It indicates that managers and owners could well have degree level professional construction and management qualifications.
Membership of the NHBC indicates that the firm is regularly involved in the construction of warranted new houses.
These logos indicate to us that formal academic training/apprenticeship support is given to it’s trainee staff.
You will see from the questions listed below that you should then look to organise a profile of each contractor into seven main categories:
Company information
Financial data
Experience of similar projects
Resources
Attitude to contractual arrangements
Health and safety compliance
Attitude to sustainability
Broken down into these categories, what follows is a minimum list of sub-questions that you should know the answers to by the time you come to make your final decision and appoint your chosen main contractor.
INTERNET RESEARCH
In the early stages, you can research a lot of the information yourself from sources such as the contractor’s own web site or visiting say the Companies House website.
INFORMAL CONTACT
Don’t waste your time researching a firm that is not interested in your project. It is probably worth contacting them informally by phone to see if they are actually interested in your project and timescales. If subtle, you could pick up quite a lot of information during your conversation.
However, as stated above, remember as a rule, certainly in the South East, a good builder/contractor do not need to search for work too hard, so thy could be put off if at the first contact with them, you hit them with a massive list of questions!
So in these early stages, a judgement call may be needed as to how far you take things to get enough information needed to whittle down the list to six that go out to tender. Remember, any gaps can be filled in once tenders are returned and you are negotiating with the finalists.
Questions to answer when researching a contractor
General questions
Trading Name?
The full address of the registered company?
How long has the firm been in business?
Company number?
VAT No?
Does the firm have an office that can be visited?
Address of office if different from the registered office?
How many owners/partners/directors?
CV/Trade background of each owner/partner/director?
Have the owners/partners/directors been involved with a company that has been wound up?
Is the firm a member of any trade associations?
Is work they carry out covered by any form of insurance backed guarantee?
Levels and type of insurances carried?
Confirmation of "all risks" insurance and up to what if any limit?
Confirmation of "Employer’s Liability" insurance and up to what if any limit?
Confirmation of "Public Liability" insurance for death and injury and up to what if any limit?
FINANCIAL checks
We would suggest that a credit check is carried out and analysed by a relevant professional such as an accountant, but there are also specialist credit check firms you could use. You will want to know the contractor has sufficient funds in the bank if things go wrong, ideally this would be in the rage of 67% of the contract sum.
Turnover for last three financial years and anticipated turn over for the current year?
Is the value of the proposed works equal to or less than 1/3 of the anticipated annual turnover of the company?
The name of a bank and contact details from which financial references can be obtained?
EXPERIENCE checks
Do they have experience of similar projects?
Address, date of completion and value of any projects of similar character to that for which tenders are invited?
Can site visits to some similar project be arranged?
Names and addresses of clients, architects and quantity surveyors connected with the projects named above to whom references may be made?
RESOURCE checks
Do they have ability to mobilise within 30 days of contract award?
If not, what is their availability?
How many projects do they have on-site at the same time as your project?
Who manages these projects?
Do they operate with an on-site project manager, full time on each site?
Can they provide CV/Trade background and training of on-site project manager?
Would it be possible to meet the on-site project manager?
Who will be in charge of project finances, issue of valuations, etc?
Do they use an independent or in house quantity surveyor (QS) to price tenders, valuations and variations during construction?
What arrangements are in place when key managers are on holiday or indisposed?
How many directly employed trades do they have?
Are all plumbing and electrical subcontractors used in possession of suitable qualifications?
Do they work with the same subcontractors regularly?
Is it possible to have details of plumbing and electrical subcontractors?
CONTRACTUAL ARRANGEMENT checks
Is the firm happy to enter into a standard form of contract such as
RIBA Domestic Building Contract 2014
JCT Homeowners Contract
JCT Minor Works with Contractor's Design 2011 or similar?
What are the firm's protocols and rates for charging for additional works?
Does the contractor charge a mark up on materials supplied by the employer and if so, how is this calculated?
HEALTH AND SAFETY checks
Is the contractor happy to act as CDM 2015 principal contractor?
What arrangements, protocols and training are in place to comply with CDM 2015 regulations 2015?
SUSTAINABILITy checks
What is the firm’s attitude to sustainability?
Do they have any experience of airtight construction?
Step 3 — Always check out the information supplied
As a minimum, it is essential that you go and look at contractors past projects and talk to their past clients. What follows is a list of questions to ask those past clients on the contractor’s performance:
QUESTIONS TO ASK REFEREES
Was a contract used and if so which one?
Did they stick to the terms of the contract?
Did they deliver the works as specified?
Did they deliver good quality?
Were there defects at the end of the project and if so how quickly did they get resolved?
Were there any post-completion defects and if so how well did they respond?
Did they stick to the programme timescales?
How well were they at managing project finances?
Did they request payment as agreed?
Were they claim conscious?
Did they try to add extras over and above the scope of works?
How good was the communication, did they keep you up to date with progress?
How well did they respond to questions when you asked them to explain things?
How reliable were sub-contractors?
Did they manage sub-contractors well?
Did they keep the site tidy and have respect for your home?
Do you think they offered value for money?
Would you use them again?
Find the right subcontractors/trades for your building project
As stated above we feel it is important to also find out about the general builder’s/main contractor’s proposed subcontractors, particularly electricians and plumbers who are key trades and are highly skilled and regulated. Since you will need to rely on them for both designs of mechanical and electrical, heating, hot and cold water elements, and Building Regulations self-certification of their work, this is highly important.
Regulatory controls on building sites are pretty loose. As with the general builder/main contractor “subbies” or “trades” can be anything from a sole trader right up to a small medium sized firm who employs a number of suitably qualified people. Instinctively, you may assume that the one man band outfits are likely to be cheaper. While this might be true as a general rule, it can come at a cost in terms of communication levels, regarding meetings, paperwork and overall response times.
In general terms, things are focused on health and safety, under the construction design management regulations or (CDM) and the building regs. So a lot depends on self-governance and compliance.
“Select a sub-contractor who understands the products you’re planning to use and has experience in applying them accurately and safely. You want to employ sub-contractors who know their trades inside out and who are able to contribute to the design and finish of your project by providing you helpful suggestions.”
The same methods cited for the general builder/main contractor above can be used to build a profile of each sub-contractor.
Selecting Electricians as sub-contractors
Electrical works are one of the most highly regulated elements of a construction scheme strictly monitored by building control. In fact, it has its own section within the building regulations (Part P; electrical safety, dwellings). First introduced in 2005 with the express intention of reducing the number of fatalities in buildings due to inadequate and faulty installation practices.
“This means that qualifying electrical work must form part of a Building Regulations submission and be inspected and approved by the building control officer. Alternatively, it should be conducted by a suitably qualified, competent electrician who can self certify the work is compliant to the council and the homeowner.”
Certification and qualifications of electricians
The work must be carried out in line with the relevant British Standards (BS7671; 2008 requirements for electrical installations, IET Wiring Regulations), to which Part P of the building regulations refers.
The Institution of Engineering and Technology (IET) produces the Wiring Regulations. This is currently in its 18th edition, with amendments just published in September 2019. It covers what your electrical contractor must know and includes the requirements for design, installation, inspection, testing, verification and certification.
To become a qualified electrician, there is a lot to learn that includes a good mix of theory, practical learning and examinations. Programs often involve traditional apprenticeships with both classroom and hands-on training spread over 2 to 3 years, achieving City And Guilds Level 2 and 3, as appropriate. There are also crash courses which provide intense schooling and assessment to get semi-skilled operatives through to Part P qualified status and beyond.
Ultimately, the qualified tradesmen will want to belong to one of the established industry trade bodies. These include ELECSA, NAPIT (National Association of Professional Inspectors and Testers) STROMA (approved inspectors), ECA (Electrical Contractors Association) and the best known of all, NICEIC (National Inspection Council for Electrical Installation Contracting).
The NICEIC has rigorous entry assessment criteria and carries out random inspections of its associates. Members can offer homeowners warranty backed guarantees for their work, which can last up to 6 years. This means that the NICEIC has to be confident in the abilities of its trades, which in turn gives peace of mind to consumers who can rely on membership as a genuine mark of competence and minimum standards of delivery.
“So, when selecting an electrical contractor for your project ensure they are Part P qualified as a minimum, and better still, are a fully paid-up member of the NICEIC.”
Selecting PLUMBERS as sub-contractors
Plumbers and heating engineers are highly skilled professionals who need to know their stuff. They’ll play a crucial role in making a project a success.
Traditionally, plumbers were involved in anything to do with metalwork on site which is why skilled trades may still be found on the roof completing flashings or flat coverings in lead.
Another area where you might typically see crossover between trades is where the above ground drainage (waste pipes etc, within the structural envelope of your property) meets the underground pipework. Installation of the latter is usually completed by the ground worker.
With that in mind, from a building control perspective plumbing and heating trades people must be experienced with and capable of delivering compliant installations under the following brackets;
Approved document F - Ventilation for all matters to do with mechanical extraction, heat recovery, passive stacked ventilation, warm air, etc
Approved Document G - Sanitation, hot water safety and water efficiency covering hot and cold water supplies, bathrooms and kitchens.
Approved Document H - Drainage and waste disposal with regard to internal waste pipes and soil and vent stacks.
Approved Document J - Combustion appliances and fuel storage systems for gas fires and gas and oil storage.
Approved Document L1A&B Conservation of fuel and power especially in relation to heat loss calculations and service installations.
In addition to the above, they will also need to comply with the water supply, water fittings regulations 1999. These essentially govern work carried out at any point from the household stopcock all the way up to the kitchen and bathroom waste systems, for both hot and cold supplies.
These are complex subjects and it takes a long time to learn how to master them. Furthermore, whilst the plumbing work that’s required in connection with the hot and cold water, waste pipes and internal drainage can technically be carried out by anyone who is competent (in compliance with all of the above), anything to do with oil and gas is heavily regulated. This means only approved, registered contractors can do this work.
Certification and qualifications of plumbers
For domestic water installations, the supply companies have all got together in order to collectively pay an annual levy to the Water Regulations Advisory Scheme (WRAS). In turn, WRAS operates the Water Industry Approved Plumbing Scheme (WIAPS). Plumbers are able to get themselves certified under WIAPS to demonstrate both their competence and an overall understanding of all the Regulations. So if you’re commissioning this kind of work it’s a sensible move to appoint contractors who are either registered under WIAPS or hold a comparable qualification.
When it comes to fuel, mistakes can be costly - so it’s no surprise that gas installations are much more heavily controlled. The two key regulators are Gas Safe and OFTEC (Oil Firing Technical Association).
It’s a legal requirement for heating engineers working with gas to be on the Gas Safe register, which they must sit through an arduous renewable certificating process every five years. It’s expensive, too, at around £3000-£5000 - plus the cost of a couple of weeks out of circulation, all of which they will need to account for in the rates they charge customers.
It doesn’t stop there, as a Gas Safe engineer must sit separate examinations (each with the same five-year renewal) for cookers, fires, unvented cylinders, warm air systems, etc. It’s not unusual for a tradesperson fully qualified in this area to have up to 10 different specific registrations.
All registered Gas Safe and OFTEC engineers should carry an identity certificate, just like a driving license - always ask to see this and check that it’s current.
As homeowners we hold accountability for our properties and the best way to prove we’ve taken a responsible approach to any work is to only appoint qualified, competent engineers to carry them out.
selecting CARPENTERS as sub-contractors
Your carpentry team may be involved in everything from erecting your home’s structural shell to fitting flooring and skirting.
Carpenters are among the few tradespeople who are likely to get involved at the start of the project and still be there right at the end when the client handover takes place. This makes them generalists in overall building, which is why so many move on to run their own companies or pursue careers in site/project management.
And yet, there is no particular mandatory training for a carpenter beyond the time they serve in apprenticeships to learn core skills for using wood-based products. So how can you ensure you employ someone who possesses all the right attributes to help you make your project a success?
The Building Regulations
Carpentry work would involve structural components like floors and roofs, along with both load-bearing walls (with timber frame construction) and non-load-bearing partitioning. Consequently, a carpenter with experience should have a thorough understanding of the relevant building regulations approved documents.
Finding a carpenter interested in the wider range of overall building standards could be a real advantage to any first-time self-builder or renovator, especially where they are coordinating the project and appointing individual trades.
Skills and qualifications
Most carpenters gain the skills and experience via apprenticeship usually reaching NVQ L2. Beyond this, there is an advanced craft certificate that can be secured in good trade activities to NVQ L3 and then on to diplomas and degrees.
From a house building perspective, the carpenter's work has changed dramatically over the past 25 years, with so much more production now being recognised and materials or components prefabricated before they get to site. Tools are largely disposable these days, so no one really needs to know how to sharpen a saw anymore. Screws are always driven with power tools and nails, more frequently from air pressure nail guns.
As a result, speed is increased on site but the final finish is often not as good as it might once have been. For instance, joinery items are now frequently pinned in position (with wood filler closing the entry holes) rather than using screws with a real wood pellets, glued and shaved into position with the grain carefully going the right way.
The modern carpenter will also expect many more components to arrive partially prefabricated, including roof trusses, internal doors and linings, window components and cabinet carcasses, to name just a few. These days, probably the most complex part of fitting a modern kitchen, besides getting things level and square, will be the installation and junction of worktops so that they appear as one.
This means that there are a range of traditional skills with some modern carpenters might not have, and as a consequence, they may not be well placed to improvise when products need careful manipulation on site. My advice is to look for professionals linked to trade bodies such as the British Woodworking Federation, the Institute of Carpenters or the Guild Of Master Craftsman, as this suggests an interest in traditional working techniques.
selecting JOINERS as sub-contractors
However, some projects are much more complex and may challenge the skills that your carpenter has, so be sure to match the right installer with the right product. In vogue at the moment is real parquet flooring, using tongue and grooved short boards laid in herringbone style, with a perimeter border to frame the floor. Similarly popular are wanting contemporary staircases using glass, stainless steel and chunky wooden sections. Naturally, these types of products need specialist installation.
Many of you will also want built-in joinery items such as window seats, wardrobes, drinks cabinets or media cabinets. Some carpenters can make this on-site but the best finish is usually obtained from a joiner who will prepare the majority of the work in his shop and only undertake the last bit of installation when the components are brought on site.
selecting Groundworkers and bricklayers as sub-contractors
Again anyone can set themselves up in the “trowel occupations” of groundworkers or bricklayers and as long as they can perform, no formal qualifications are needed.
Skills and qualifications.
The usual route into bricklaying (but also groundworkers to a degree) is via an apprenticeship. Usually taking a minimum of a year, generally split between some classroom training but mostly site work, leading to either NVQ2 or NVQ3.
With bricklaying, these are designed to ensure that the student becomes competent in brick bonding, motor applications, wall ties, reinforcement, cavity trays, damp proof courses (DPCs). They will also gain a little knowledge about ventilation and insulation. More advanced skills such as the construction of chimneys, brick corbelling and arches are usually obtained through experience and mentors on site.
A groundworker’s apprenticeship should focus on the installation of the drainage and services, how to support open excavation safely, concrete work, basic reinforcement, the correct use of plant (heavy machinery) and so forth. Setting out-the process of establishing the precise location of trenches etc is a particularly important part of the training. When it comes to operating plant, certain equipment requires a better range of skills. Dumpers with front tipping hydraulic buckets, wheeled and tracked excavators (both 360° and 180° rotation) and lifting apparatus are the most common types for domestic projects. To show they are suitably qualified, individuals can obtain a CPCS (Construction Plant Competency Scheme) card, currently referred to in the trade as a ticket or license.
All apprenticeship programmes should instruct the individual on how to interpret construction drawings, effectively communicate with others stakeholders on the site and, particularly relevant today, acquire minimum standards in both planning and practically applying health and safety.
Membership of one of the trade leading trade associations (such as the Guild of Master Craftsman, Guild of Bricklayers and Federation of Master Builders) may imply a higher focus on quality, as well as traditional skills and values.
By definition both groundworkers and brick bricklayers will do so, whether they think they do or not. This is because it is rare that all of the necessary information will be on the drawings and specifications and they have to interpret it.
Selecting ROOFERS as sub-contractors
Consider that by definition roofing involves working at height. Secondly, different coverings and constructions may have similar applications, but require alternative levels of skill to apply.
Skills and qualifications
Correctly trained roofers will have served their time as apprentices or be able to demonstrate that they have some specialist skills in a specific area through more direct training. For general operatives to largest trade bodies the National Federation of Roofing Contractors (NFRC) and the Confederation of Roofing Contractors (C0RC), could be approached with complaints if anyone was dissatisfied with a member's performance, like with the Federation of Master Builders (FMB).
Flat roofing specialists can join the Mastic Asphalt Council (MAC), Single Ply Roofing Association (SPRA) or the Lead Sheet Association (LSA). Let’s take the LSA as an example. Someone with roof construction knowledge such as a roof tiler could get to a Level 2 NVQ in lead sheet work in a matter of months if they want to fast track their training. Alternatively, you can do a five-day basic bossing (shaping) and welding course for just over £600, which would provide some level of confidence. Lead work used to be the core skill of the plumber, and no doubt that it still is. However, many roofers have ceased the chance to upskill and include this in their service; and quite rightly so.
Coverings such as thatch and metal (zinc and aluminium are popular options) require specialist skill to fit, and these jobs should always be completed by a suitably experienced professional. Good points of contact for installers include the National Society of Master Thatchers and the Federation of Traditional Metal Roofing Contractors.
Selecting PLASTERerS and DECORATORS as sub-contractors
Much like many of the other trades that are likely to be involved in your project, the recognised form of training for a plasterer decorator is through and approved apprenticeship - whether, they specialise in internal or external work. There is no substitute for learning skills application techniques from more experienced tradespeople, as this is simply the best way for a professional to get to grips with delivering a wide range of work to the right standard in a timely fashion.
Many contractors in this sector will join trade bodies such as the Guild of Master Craftsman, and Federation of Master Builders to support their skills and training.
A word about specialisation
Renderers tend to specialise between cementitious applications and lighter weight acrylic options (but not both), while internal plasterers may not undertake external rendering at all. Furthermore, some plasterers may not be prepared to consider dry lining (as a drier trade), and some decorators might specialise in paint coverage only, and not be interested in alternatives like paperhanging or marble texturing, etc.
So it’s essential to get someone with the right skill set to match your specification and not let availability alter the way your house is built. To be clear about terminology, rendering mortar is applied externally and plastering mortar internally.
External rendering
Rendering is usually applied either to ensure a good waterproof external envelope or for aesthetic reasons, to achieve a traditional or contemporary material finish.
Cement and acrylic renders are quite different treatments, and therefore it requires different skill sets from contractors. The acrylic versions are especially popular for system builds. With this type of products, completing specific training courses from the manufacturers is necessary to secure the guarantees. It would probably be best to go to a tradesperson from their approved list of firms-but, this can mean you end up paying a premium.
The advantage of acrylic renders is that they are more forgiving, as they have inherent flexibility to them with slightly elastic characteristics. They have very thin render coats, usually between 1 and 3 mm, and might go onto a special backing board or directly onto a masonry substrate. You can choose pre-coloured renders, and some have silicone and additives, which helps to give them an element of self-cleaning.
Traditional sand and cement render is typically applied in two or three coats. The golden rule is that the mortar mix being selected (which will be made up of sand, cement and lime) must be weaker than the substrate material behind it. It’s a classic mistake to use a lightweight thermal block externally, and a hard cement render over the top, which will lead to inevitable render cracks. With a softer render mix there will be more tolerance over the hard brick or block behind. The first coat should be around 12 mm and subsequent coats less than this, typically 6 mm. Another good tip is to use a plastic reinforcing mesh in your cement scratch coat, which is another way to help prevent cracks developing. You will need to allow for painting the render in your budget unless you’re leaving the same natural colour as the finish.
Some renders might be textured, with cement options typically being dashed by adding aggregate (wet or dry) into the mix. Much finer aggregate is used in the acrylic renders, which is then dragged or rubbed with a sponge to develop the texture following application.
Plastering
Your internal finish starts with a decision to either dryline (tape and joint plasterboard) or to plaster bond and skim your wall and ceiling services. These are quite different skills. In the case of new homes, system builders probably tend towards tape and joint filler; whilst more traditional construction techniques, it’s common to go for two coat wet plastering.
A word about lime
Lime-based renders and plasters are normally used with traditional buildings in refurbishment and restoration (although they can work well within some new developments, such as when you’re using a natural construction technique).
Unfortunately, lime is generally misunderstood and, unless someone has been properly trained in its use, they are likely to get some (often all) of the principles wrong. It is a much more sympathetic material, being softer and less brittle than cement. As a mortar mix it has some self-healing characteristics (which can help manage thermal movement). It also has breathable properties that can absorb and evaporate moisture effectively.
If you want to use lime based mortars on your build then you will need to ensure your contractors are properly scored in these techniques and that they fully understand the difference between line party, hydrated lime and natural hydronic versions and when each type is appropriate. It’s a very specialist area and is incredibly easy to get wrong if you use inexperienced teams.
Decorators
If you pick your contractor wisely, their skill could make a huge difference in the quality of your build. It’s not just about colours but also about the type of paint, the thickness and frequency of coats and of course the preparation. Some paints are hard-wearing, others easy to clean; some light-reflecting; others help to buffer moisture with naturally absorbed properties. Choose an experienced and knowledgeable decorator will help you achieve the right finish.
kick-start your project
Congratulations! You should now have crucial information relating to creating a shortlist of contractors you could now go out to tender to.
“If the steps needed to select the right builder/contractor and related sub-contractors to ensure your project is a success seems too daunting then let’s talk. Harvey Norman Architects can help you wade through the steps required and make sure you aren’t ignoring any vital elements that could result in a costly project that does not go to plan.”
We offer a stand-alone no obligation “Kick Start Consultation” where Harvey Norman’s Director, Ian Harvey will identify the specific requirements relating to your project and your available options.
Typically, this service saves our clients thousands of pounds and weeks of lost time, not to mention the anxiety and headache of getting something wrong. However you choose to progress, we wish you success in your project!