Loft Extension Cost
Converting and extending a property at loft level
There is no doubt that not only is it easier to extend than to move, it is also usually cheaper to do so! If you've got some unused space such as a loft, it's worth thinking about building into that unused space to create useful additional living space. The exact type of loft conversion or extension that will be the most suitable will depend on the type of roof and how you intend to use the loft space, but the most common conversions are internal loft conversions and dormer conversions, though there is another type of loft conversion which involves a full removal of the existing loft and building a new loft. Internal loft conversions are the cheapest and require minimum building work so are most popular with DIY enthusiasts. But dormer conversions are the most popular type of loft conversion in the UK due to the additional space they offer by extending the property at loft level. Full removal and build loft conversions offer the most flexibility but are the most complex in terms of building work and therefore the most expensive by far.
Average loft extension costs
Things to consider before converting or extending your loft
Unfortunately, not all lofts are actually suitable for a loft conversion or extension. Before you start planning your loft project, you need to check that the roof structure is suitable and that there is enough height within your loft to provide adequate headroom. You also need to think twice if there is a chimney in the way of your proposed conversion, as the cost of moving a chimney can be considerable.
If the existing head-space is insufficient then there are types of loft conversions and extensions which can still work but they are much more expensive as they generally involve removing the old loft and fitting a new one with more headroom. Mansard loft conversions involve one or both slopes of the roof being replaced with a new structure with steep sides and an almost flat roof is placed over the top creating sufficient volume for an additional storey. Another option when headroom is limited is fitting a pre-fabricated loft, replacing the existing roof structure with a larger one that is craned into place and can extend out over an existing extension. Both these types of loft conversions will normally require planning permission.
Doing it Yourself
As long as you have a typical roof structure and no restrictive planning constraints, a loft conversion and/or extension can be one of the most straightforward methods of getting some extra space. Of all the methods of extending your home, a loft conversion is probably the most suited to the DIY enthusiast, particularly if you go for a straightforward internal loft conversion with no dormer or other windows required and just plan to use the loft as extra storage. Assuming you have in place all the relevant permissions and paperwork required, the first step is fitting the flooring. If you already have good wooden floor beams, then this step is really easy as all you really need to do is fill the gaps between the beams with insulation, then lay floorboards on top across the beams. Next, come the stud walls which are then covered in plasterboard and tacked in place using nails or screws. This is a bit more difficult, especially where your loft walls are angled. Once the plasterboard is tacked in place, you should probably hire a plasterer at this stage to get a professional finish.
To convert your loft into a living space, such as a spare bedroom, is a bit more difficult. You will probably need a structural engineer or architect to check that the added load of an additional room will be supported, plus you will need to submit plans to building control to ensure you meet Building Regulations. Windows or roof-lights will also be required, typically just roof-lights to the front and back, but windows can be added to the gable walls. Note that fire escape windows will be required with an opening large enough to meet the Building Regulations.
Converting your loft into a living area will also require a proper staircase to meet regulations. The design and position of this staircase are the key decisions in any loft conversion and the stairs must land where there is at least 1.9m of headroom with a maximum staircase pitch of 42 degrees and a useful minimum width of at least 600mm. Spiral staircases are popular in many loft conversions as they are a space-efficient option. Extending the loft space is an even bigger job, if considering this it would be wise to consult an architect or professional construction company.
Loft extension checklist
- Loft conversion companies can work around water tanks and chimneys in the loft space but try and plan around them if possible
- If the loft extension is to be used as additional bedroom(s) consider adding a bathroom as part of the loft conversion
- When planning be careful that the loft extension does not compromise space on the second floor just to accommodate the staircase access
- Consider that your boiler may not be able to cope with the extra pressure required to feed hot and cold water up to another floor
Hiring a Tradesman Checklist
- Always get at least 2 quotes before hiring.
- Never pay the full amount upfront.
- Get the quote in writing.
- For any payment you make, always get a receipt.
- On more expensive jobs, ask for references.
- Check if the tradesman is a member of any trades associations.
- Make sure the tradesman has public liability insurance.
Does my loft have enough height for headroom to be converted or extended?
Do I need Planning Permission for my loft conversion or extension?
Where will the new stairs go?
Will a loft conversion/extension add value to my property?
Will I need steel beams to reinforce the new floor/ceiling?
We need to convert an existing room into a dormer to make more space. No extra plumbing, stairwell etc. required. The property is a terraced house and the conversion will be the top room at the back of the property so no planning permission is required.
Submitted by Emrys
Convert existing pitches roof into a dormer roof construction that functions as a master bedroom with en-suite bathroom.
Submitted by Lau
Hi, I want to make a loft but the builder is so expensive.
Submitted by Iram
Hi, I have a loft with access with a ladder and would like a loft conversion with a dorma window.
Submitted by Shabnum
Hello team, I am looking to do a total renovation of my house. I want to put in a loft conversation with an ensuite if possible, new kitchen, new bathroom, all rooms skimmed and painted. New fixtures and fittings throughout the house including a little bit of work outside. I know it is difficult to...