How to Build Quality into Your Home

Can you build ‘quality’ into your project? There are two ways of answering this question. The obvious one is to specify lots of expensive materials: handmade bricks and oak flooring, or perhaps a fancy bathroom suite. That’s quality, for sure, but the other side of the quality issue – and the one we seek to address here – concerns standards. Put another way, the question might be rephrased as, ‘How can I best avoid making mistakes?’ There is no simple answer to this but there are lots of useful pointers which can highlight likely problem areas.

Management

You can save a lot of money if you undertake the project management yourself, and lots of inexperienced self-builders embark on this route armed with little more than enthusiasm and determination. But this path is not without risks, and there is a good chance that you will miss important details during the build without some supervision. Building inspectors and warranty providers will visit the site and provide some feedback on what’s going on, but in reality, their visits are very limited in number. So be prepared to pay for some quality control – an architect, surveyor or a ‘professional friend’ – to oversee what you are doing and to call on if you are in any doubt as to the quality of the work being carried out for you. If, on the other hand, you hire a builder to run the project, part of his job description should be to make sure that the work is carried out to a good standard. Probably the best way to ensure this is to vet his work before hiring him by talking with previous clients. People tend to forget the cost of building work very quickly, but they don’t forget the errors and omissions.

Design

Don’t skimp on design fees. Get a properly drawn set of dimensioned plans and ensure that the details are thought through. Whilst almost all errors can be attributed to poor workmanship, this often stems from inadequate instruction. It is sometimes said that most building mistakes occur in the gap between design and construction.

Avoiding Major Defects

The structural warranty providers pay out vast sums each year to projects which turn out to have serious defects. The two most common (and expensive) failures concern foundations and cavity walls. Cavity walls can be avoided altogether, but this doesn’t necessarily avoid the risks associated with rainwater penetration of walls. Common errors include mortar bridging the cavity, and cavity trays being omitted or installed incorrectly. You should be able to watch for these errors if you oversee the construction. Foundation problems are more difficult to eliminate, though increasingly builders are choosing to put everything in the hands of a structural engineer from the word go. Even so, subsidence can occur at a later date, and this is sometimes caused by human error on site — for instance, drains being installed incorrectly, leading to a failure of foundation support. Again, supervision at the time is probably the best insurance against things going wrong later on.

Energy Efficiency

Airtightness is now measured in new homes and the level of airtightness is, to some extent, a quality mark in itself. Modern homes should not be ‘leaky’ and the Building Regulations standard of ten air changes per hour (under pressure) is very easy to meet. The best built homes will be scoring less than five (i.e. half the Building Regulations standard), sometimes much less. The German PassivHaus standard (regarded as the gold standard for low-energy builds) requires a score of less than one. So look for a good airtightness score when the time comes to test. In contrast, there is no way of measuring how effectively thermal insulation has been installed: only close supervision can ensure this is done correctly.

Underfloor Heating (UFH)

Wet systems must be designed well so that the heat is evenly distributed, and this needs to take floor finishes into account, as the heat output is very dependent on the cover above. Ideally, UFH should not be installed beneath cupboards, wardrobes and kitchen cabinets, nor where it is likely to be drilled to take a fixing (i.e. sanitaryware). Also, with wet systems, care should be taken to ensure anti-freeze is left in the pipes if they get pressure tested before the house is complete, as there is a danger of freezing. Electric UFH mats can get shredded by floor tilers who don’t realise what they are cutting tiles on.

Glazing

Misting sealed units have long been a common fault, but it is largely eliminated with factory glazing; although this brings its own problems — damage to glass on site is especially common when rendering is taking place after the glass has been installed.

Avoiding Cracks

Cracks in plasterwork are usually not harmful but can be disruptive, especially when they appear after decoration has been completed. It’s a common feature in block - work homes, especially where the blocks are lightweight and the renders are cement based. Some plasterers now add fibres to the render but it is not altogether clear whether this entirely eliminates the problem.

Squeaky Floors

The culprit is usually timber joists, which shrink as they dry out. Solutions include using dimensionally stable, kiln-dried timber which doesn’t get left outside and also, increasingly, timber engineered joists, such as I beams and posi joists. Make sure that plumbers and electricians know how to use them. If they cut through the top, they will have to be replaced.

What is Bad Finishing?

LEFT TO RIGHT: Miscalculated foundations, frozen underfloor heating pipes, misted double glazing, creaky floorboards, cracked plasterboard

Many self-builders wonder exactly what finishing standards are expected of the building trade and whether the finishes on their home are acceptable. It’s not an easy question to answer as everyone has different perceptions of what is good enough. However, there is now a really useful document, published by the NHBC, entitled A consistent approach to finishes, which covers most of the areas of contention and sets a benchmark for what is and isn’t acceptable. It’s available for free download at nhbc.co.uk.

Snagging Checklist

Even the best builders will leave behind a list of problems – however small – that need to be rectified. This is why most building contracts include a retention clause withholding some money – usually 2.5% of the contract fee – for six months after completion. This final payment should not be made until all work has been carried out to your satisfaction.

A ‘snagging’ check, carried out before this payment is made, looks for everything from ensuring the insulation has been correctly installed, down to making sure the doors open and close properly and none of the glazing is scratched. This check is essential, but it can be a touchy subject between client and builder, so to avoid souring your relationship, follow our top tips:

• Retention clauses often rely on the contractor doing their own snagging, so make separate arrangements before the building process begins, and outline them clearly in the contract.

• If you’re confident you are up to the task, then get hold of a snagging checklist from the NHBC Standards or a specialist company such as Snagging.org.

• Most people would be best advised to bring in a third party to snag, meaning the process is carried out by a professional who is trained to spot even the most hidden problems.

• Ensure a Completion Certificate is issued on finishing the project, as you will need this to sell the house.

Further reading:

• How to get the most from your House Designer 
• So You Want to Be a Project Manager?
• The 12 Steps of Self-build
• Cut Costs Not Quality