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Builders for loft conversions

Loft conversions can be a great way to add value to your house and provide that much needed extra room without breaking the bank. No stamp duty is needed, or planning permission (subject to certain conditions - see below) and stress is kept to a minimum compared to the alternative of moving house. Here we detail some of the things to think about when looking for a builder.

Planning permission

According to Planning Portal a loft conversion for your house is considered to be permitted development, not requiring an application for planning permission. It is however subject to the following conditions:

40 cubic metres is the maximum additional roof space for terraced houses

This rises to 50 for detached and semi detached properties

You can't extend beyond the 'plane' of the existing roof slope

You can't extend above the current maximum roof height

There are no verandas

A few other criteria - check the site Planning Portal for more details.

Your builder will/should be aware of all of these requirements when designing out the build, but best to be aware of these rules before you start thinking about undertaking such a project.

A risk for you and the builder

While loft conversions are often considered the easiest and cheapest way of adding that all important extra bedroom, 36 per cent of British builders and tradesmen surveyed by Direct Line Home Insurance said they are the most problematic home improvements.

An articles by This is Money highlights some of the areas.

James Gold, of Landmark Lofts, told This is Money: "First of all, neighbours will need to be notified about the conversion and any party wall issues. Although they can’t stop a project from going ahead, they can request a survey before and after the works have taken place. Additionally, you need to make sure you know what you’re working with. At least 2.1m of head height is required within the loft itself which is measured from the ceiling joints to the ridge."

Another area is budget control.

Only 26 per cent of home improvement projects tend to run beyond the original budget and timeframe, the 100 builders and tradesmen surveyed said.

Carrying out any form of home improvements requires proper planning, realistic budgeting and knowledge of any applicable planning permission requirements.

Agreeing a quote with builders before any work starts can help prevent future problems. This is the great thing with using Priceatrade.com - now you can set out the requirements item by item and know the costs up-front.

Give thought to exactly what you want: a roof window or dormer; will it be en suite; and do you want it tiled or slated? The more detail you hink about now the better.

Prep work with your builder

Some things you and your builder will ned to check/discuss:

Can your home take the weight?

You’ll need to make sure that the structure of the building can take the extra weight. Your builder will need to expose the foundations and check them, together with any beams or lintels that will be asked to carry more weight.

Your builder will need a Building Control officer to check all these elements, including digging a small hole to expose the foundations. If it turns out that your house needs underpinning to support the extra weight, it could double your budget before you start.

Is there enough head height?

Your builder needs to map out how uch headroom you’ll have in your loft once it’s converted – people are often disappointed. Don’t forget you’ll have to accommodate a staircase leading up into the loft.

Also your builder will need to plan where things like the water tank and various plumbing goes. The heating and hot water system may have to be replaced with a sealed system. It’s better to have an unvented hot water cylinder than a combination boiler, but it will take up a cupboard-size room and your builder will need to inlcude this in the plans and costs.

Building Regs

Loft conversions always need approval under Building Regulations (irrespective of whether they need planning permission).

So it pays to adopt the full plans application approach and have a detailed scheme approved before you find a builder. Having an approved design will take much of the risk out of the work and also mean the builder has a chance to give you a fixed quotation, rather than a vague estimate.

If your house is semi-detached or terraced don’t forget to notify your neighbour of your proposals, which will usually fall under the Party Wall Act 1996. Your Building Control officer will inspect the work at various stages and on a final inspection should issue you with a completion certificate – don’t settle any final accounts until you’ve received the certificate.

Loft stairs

Careful with the plan for the stairs - purpose-built staircases are around 10 times the cost of standard (off-the-shelf) designs, so bear this in mind.

If you do need a purpose-built staircase, it pays to have the design approved by your builder and Building Control officer before you actually start the build. NB: your stairways should lead to a hall and an external door. If you have an open-plan arrangement where the stairs rise from a room, it is likely you’ll have to alter it, fitting a new partition wall or choice of escape routes.


You don’t need to make a lot of structural alterations to accommodate skylight windows, which makes them relatively easy to fit.

Dormer windows may be essential to maximise the headroom in the loft and provide useable space, but will need to be supported at the apex point (ridge). A ridge beam is installed beneath the apex before the dormer roof joists can themselves be fixed in place and the roof weathered. Talk to your builder to agree these plans.


Loft conversions have become awkward to insulate. The sloping ceiling will need insulation cut and fitted between the rafters, and on top of them.

The new floor also needs soundproofing, and this is easily achieved by laying a mineral fibre quilt between the joists. Your builder should also consider insulating any party walls, both against heat loss and noise.


When you convert your loft you are, of course, going to lose storage space. Make the most of what you have by using the eaves behind the ashlering – fit access hatches.

Be clear with the builder

Check with the builder what is and isn't included in the quote. Will the builder arrange a skip to take away rubbish or will you have to organise and pay for that separately? Does the quote cover installation of power points and/or lighting? If you have a friend who is a builder or surveyor ask them to look it over.

When you are happy with your choice go through the contract in detail with the firm. Remember, anything you decide to add at a later date is likely to cost more, so if there are things you want now is the time to try and include them. Let them know if they agree to include them in the price you will give them the contract. Ask for a bit more than you anticipate achieving – you can always come down.

Cheap does not equal best

This isn't about cutting costs – it is about getting good work at a decent price. When quality of workmanship and materials are involved this should have a huge bearing on your choice.

Hopefully the quotes you receive will be reasonable, but if one is significantly more expensive (make sure you are comparing like for like) and you wish to use these builders, query it with them, allow them to see the other quotes and give them a chance to explain and revise their quote.



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