Loft Conversion Questions

Like you, more and more people are finding that trussed roofs just do not allow them to extend into the roof space, so it is quite usual for us to do this kind of work.

In most cases, the only way to make use of that extra ‘room in the roof’ is to actually take off the whole of the existing roof and replace this with a purpose designed and engineered new ‘attic space’ roof.

While sometimes there are ways around this, or areas where it may be possible to preserve some of the existing roof, total replacement often turns out to be the fastest and most economical solution.

Send us your dimensioned drawings, or sketches, of the elevations and plan that you want and we will be pleased to give you budget prices for various elements of the work required.

However, please bear in mind that the costs of this will depend on a number of things, for example:-

• The ‘footprint’ of the floors below the new roof
• The shape of this and of the new roof
• The amount of space and number of rooms you want
• What the rooms are to be used for
• Stair access to the new roof
• What windows, dormers, roof lights, etc. you want in the new roof
• The spans (distances) between supports for the new floor
• Where in the UK your property is.

Other things you will need to check to see whether what you have in mind is going to be possible are:-

• Whether the existing walls below the roof are strong enough to carry the new roof and rooms that you propose. 

This will depend on when the house was built and how the structure was designed. You may need an engineering survey to get confirmation of what has to be done. If necessary we can arrange this for you In most cases this turns out to be OK

• Whether the work can be done under the ‘Permitted Development’ rules for town planning

If so, then ask your Local Planning Department for a certificate confirming this. If not, then you will have to get full drawings and other documents prepared and submitted for planning permission before the work can start. It is also advisable to make sure you have got permission before spending money on the Building Regulation drawings in order to get approval for the construction from your Building Control Department.

To save you money, we can prepare professional sketches (from your rough design & photos) for you to discuss with the planning officer.
When you have got agreement with her/him on what will be permitted, we can then produce the drawings and documents for you to submit yourself (or we can do this for you).

As soon as you’ve got planning approval we can also prepare everything you need, e.g. engineering and energy calculations as well as specifications and drawings, for you to submit for Building Control approval (or again we can do this for you).  As LABC Partners, we can obtain Building Regulation Approvals anywhere in the UK.

You may, of course, have your own architect / designer who can handle both planning and building regulation requirements for you. 

If so, we will be happy to work with them to achieve what you want.

When all of this is in order, we will produce the structural design, manufacture and build the new roof for you.

This can either be:

• just the skeleton structure,
• made wind and watertight with windows fitted,
• semi complete with fascias, soffits, barge boards, roof tiles and guttering etc. fixed, or
• fully complete with internal walls dry lined, doors and joinery fixed, etc. ready for you to decorate.

In most areas of the UK our services are completely flexible for you to get us to do as much or as little as you wish.

“We are interested in replacing our existing roof which has too low a pitch to convert to enable us to expand our home. The house is a timber frame kit house with block built exterior walls. We have been told that we cannot replace the roof as the roof is 'tied into the house', is this right or can it be done without gutting the whole house?”

As ever, I’m afraid there is no simple ‘Yes’ or ‘No’ answer.
However, hopefully the following will help with your initial considerations.

1. In principle you should be able to extend upward without ‘gutting the whole house’

2. Increasingly we are designing, engineering, manufacturing and building a whole variety of ‘upward extensions’ as:-

1. Rooms inside a new roof 
2. Complete new walls on top of the existing rooms below, with a new roof on top of these. 
3. Additional space inside the new roof. 
4. We do this for bungalows, houses, barns, blocks of flats, warehouses, factories, etc. … 

so see no major problem with achieving what you require.

3. However, a definitive answer to your question will require sight of:-

1. Your original construction drawings 
2. Your proposed extension drawings. 

4. The support needed for the new upward extension is provided:-

1. In many cases by the existing lower walls 
2. Where the floor plans do not quite coincide, by the use of beams spanning between these. 
3. If the upper floor is larger than, or goes outside the existing walls, by sturdy timber posts placed on pad foundations. 

5. In extending a timber frame building upwards it is important to remember that it is the timber frame that is the structure.

1. This supports the upper floors and roof and all the loads placed on them. 
2. The timber frame wall panels will also provide lateral support for any external masonry walls. 
3. Some of the internal timber frame walls may also provide intermediate support for the floors and roof. 
4. All load bearing walls must transfer all these loads via firm foundations to solid ground. 

6. Your structural timber frame will have an integrally engineered design.

1. Lateral support for this is likely to have come from first floor joists, ceiling joist, rafters and some cross walls. 
2. Calculations for this will have taken account of any side loadings on the external walls, e.g. from prevailing winds. 
3. The structural engineer will have used national tables and graphs of what these loads are in her/his calculations. 

7. The design of your existing roof will be important.

1. Are any gable ends to be retained in the new roof / upward extension? 
2. If it has a ‘cut’ roof, how do the rafters, ceiling joists, purlins, ceiling beams, struts and props work together? 
3. If it has ‘trussed’ rafters, how and where are these fixed to the walls below? 

8. Providing the integrity of the structural frame can be retained, there is no reason why the roof cannot be replaced.

1. This could be achieved by, for example leaving ceiling joists in position to cross brace the timber frame walls 
2. Adding additional temporary, or permanent, cross bracing before any integrally essential roof timbers are removed. 
3. Taking down gable end walls and replacing these as part of the new upper floor and roof design. 

9. Since you have block faced outer walls, consideration needs to be given to how these will continue upward in the new extension.

1. If the new upper walls are to have a masonry facing on top of the existing, the foundations must be checked to ensure they give sufficient support. 
2. If the new external facing can be render, tile or slate hanging, timber cladding or similar, these can be fixed to the new timber frame. 
3. If you house is no more than 2 (possibly 3) floors high, it is likely that in (b) the existing timber frame will be sufficient to carry at least one additional floor and roof. 

10. While all of this may sound complicated, your Local Authority Building Control (LABC) office will have plans and other details of the way the house was constructed.

1. They should be able to answer most of the construction points raised above. 
2. As LABC Partners we can liaise with them on your behalf if you are in England or Wales. 
3. If your property is in Scotland we may be able to get similar collaboration. 

11. You should also consult your Local Authority Planning office about the extent of the extension they will allow. They are generally concerned about:-

1. The effect on neighbours, e.g. roof height overshadowing, privacy from windows overlooking, retaining building lines 
2. Complementary appearance, e.g. general design, windows, materials, etc. 
3. Conservation & National Park areas, listed buildings, etc. 

As you will appreciate, the above is offered as general information and must not be taken as specific advice.