The process of designing your loft conversion will naturally evolve from early sketch ideas to a final agreed layout suitable for a planning application (if required) and eventually to comprehensive working drawings.

The first stage of any project is to find out if your loft is suitable to convert and to obtain some initial design ideas on what may be possible. We have termed this the feasibility stage although you may come across numerous other terms for this initial process such as a property assessment or viability study.

Even for straightforward conversions, it is important to be sure that you have looked at all of the options open to you and gathered as much information as possible before you proceed with a specific design. It will cost time and money to change your design later on and, when all the work is completed, you should be satisfied that you have the best solution for your needs.

We would strongly recommend that you use an experienced architectural designer to carry out your initial scheme design as they will be familiar with the limitations that are imposed by planning and building regulations. They will also know how to make the most of the space available.

myhome mygarden can provide you with a comprehensive Feasibility Study for any proposal that you are considering.

At the feasibility stage, you should be considering the overall design of your loft conversion and not be overly concerned with details such as your choice of finishes.

The main considerations you will need to think about at this stage are listed below.

A. Your Requirements

Often know as the 'Client Brief', your first task is to define what you actually require from the conversion. It is a good idea to involve the whole family in this process as people may have different priorities. It may also help to speak to someone you know who has had work completed recently as they will have gone through this process.

You will need to decide on the number and use of the rooms you require. You may be looking to add a room that is multifunctional, such as an occasional guest room, which you can use as a study or TV/Play room for the rest of the time.

Most designers like to have a clear Client Brief from you so that they can help you to create the space you need. Create a list of priorities, dividing it into essential works and desired, but not essential works.

Does the extra space need to be a certain size for a specific reason? If you are creating a study, for example, you will need enough room for a desk, chair and storage. If you are looking at creating a new bedroom, does this need to be double or single and will it have an en suite?

Our best advice is to plot furniture on to your initial plans - if your designer is using a modern CAD package, this will be normally be easy to do or you could always use the cardboard cutout method! Be aware that floor plans for lofts can often be misleading as the headroom may be very low in some areas. Ask your designer to clarify which parts of the loft will have normal headroom.

B. Headroom

Many loft spaces can not be converted and meet the building regulations as they have insufficient headroom.

You may appear to have enough space but remember that converting your loft will involve the installation of new floor joists and these will raise the floor level from the existing ceiling joist timbers.

Also, the ever changing regulations on thermal insulation will reduce the height of the loft as the insulation will need to be fixed to the underside of the rafters.

The building regulations require a finished headroom of 2.0m over the new staircase and this will generally dictate the minimum height of the rest of the loft. We would normally expect the existing loft to have a minimum of 2.4m clear space for it to be suitable to convert.

In some cases, it may be possible (and necessary) to completely remove the roof and raise the height but this will almost certainly require planning permission and is likely to be costly and potentially controversial.

C. Windows - Dormer or no Dormer

Loft conversions may need to be formed using a dormer window in order to create the additional space you require. This type of construction involves removing an area of the existing roof structure and forming an extended roof area as shown in the examples below.

The overall usable area of your loft can be significantly increased by incorporating one or more dormer windows in your design. However, be aware that this type of construction may result in you needing to apply for planning permission (see our factsheet on Planning Permission for Loft Conversions for more details).

If you live in a conservation area or a listed building, the size of any dormer is likely to be further limited.

The alternative to dormer windows is to include rooflights which will provide plenty of light and can be grouped together for added impact. If your loft has sufficient headroom, then these can be an ideal solution as they are less expensive and generally do not require planning permission. You will also gain up to 40% more light from a rooflight compared with a normal ‘vertical’ window.

It is possible, of course, to have both a dormer and rooflights and it is quite common to have a dormer to the rear and rooflights to the front.

In all cases, give consideration to the positioning of your windows as lofts can provide fantastic views of your neighbourhood.

Be aware that the Building Regulations limits glazed areas and this is a subject that your designer should be able to help you with.

D. Stairs

Designing the staircase arrangement into the loft can be extremely complex and is almost certainly one of the most important design considerations for any loft conversion . There are numerous regulations on new staircases which will limit where the staircase can be fitted - in particular you will need to comply with headroom and fire protection requirements.

Where possible, the new loft staircase is often located over the existing staircase (if you have one) as this tends to minimize the space lost in the existing property.

You will need to decide if you are prepared to lose the use of, or reduce the size of, an existing room in order to fit your new staircase.

If space is tight, you may consider the use of a ‘spacesaver’ stair which utilizes alternating treads as shown in the example.

Staircases will usually need to be located in a landing area as, except in bungalows, they are not permitted to discharge into an existing bedroom (see also item F below).

We would recommend that you leave the design of your staircase to an expert as you are unlikely to be familiar with the limitations and they will often know the best way to find a solution.

E. Structural Alterations

Be aware that most loft conversions will require considerable alterations to the existing roof structure in order to support the new loads. You may require the addition of one or more steel beams – the final design will usually completed by a qualified structural engineer.

In converting the loft, you are changing the space from a storage area to a proper habitable floor space and this will require an increase in the strength of the supporting structure. Floors have to be designed to carry a greater load than ceilings.

Most loft conversions will result in changes to the roof design and existing ties and struts may have to be removed to make the space usable. This will result in a need to support the roof in a different way.

If your roof is trussed (W shaped pre-formed components as shown below) then converting the space is likely to be more complex as you will probably have no internal load bearing walls and the existing timbers will be of a reduced size. Also, great care should be taken when converting this type of loft as removal of the existing struts before the roof is properly supported could be disastrous.

A well prepared feasibility study will give you a good idea of the structural alterations required for your conversion.

F. Fire Protection

There are many aspects to the fire regulations that relate to loft conversions which will be considered by your designer and these are summarized below:

Escape route – for most lofts, you will need to provide a protected route form the loft rooms to an outside door. This is intended to provide 30 minutes for anyone in the loft rooms to escape the building in the event of a fire breaking out in another room. Existing doors off the landing or hall will need to be upgraded to fire doors (excluding bathrooms or WC’s). The staircase itself may need to be plasterboarded and plastered below to provide 30 minutes protection. Any glazing will need to be changed to fire resistant glass or removed and blocked in.

New Doors – new doors to the loft rooms (except bathrooms and WC’s) will need to be fire doors and there must be a fire door between any new loft room and the landing. This can be located at the loft landing level or the existing first floor level.

Smoke alarms – mains operated smoke alarms which include a battery backup will need to be provided to all floors (usually in the halls and landing areas). The alarms will need to be interlinked so that if one goes off, they all go off

Ceilings – existing first floor ceilings will need to achieve 30 minutes fire resistance. This may require additional plasterboarding and plastering.

Sprinklers – many councils will accept a small sprinkler system as an alternative to the above protection requirements but these can be expensive, particularly if your mains water pressure is low and water storage is required. Your designer or local Building Control Department will be able to advise further on this.

Reduced Standard – for some smaller lofts and bungalows, the Building Regulations allow for a reduced standard and many of the above requirements will not be applied. This can be established at the feasibility study stage or for further details, ask our experts.

Whilst the fire regulations may appear exacting, it is worth remembering that in  the UK in 2005 over 46,300 homes caught fire, killing 287 people and injuring 9,700 others.

G. Water Tanks

Many loft conversions will require alterations to the plumbing and heating system as the existing tanks will need moving.

You will need to consider where the tanks can be relocated to or whether they should be changed to long, thin ‘coffin’ tanks.

If you are installing a bathroom in the loft space, the tanks will need to be positioned higher than the water outlets, particularly the shower valve. You may need to install pumps if this can not be achieved.

We would recommend that you consider changing your system to a ‘pressurized’ system as this does not require a water tank although a special hot water cylinder will need to be installed. An alternative is to install a combination boiler but these are generally only used for smaller properties.

H. Budget/Value Considerations

There is sometimes a reluctance to talk about budgets at an early stage, but this can often be the single most important factor that determines your final design.

Whilst you will be building the space for yourselves, we would always recommend that you consider the resale value of your home once the work is completed. The conversion will need to blend in well with the existing property and the overall effect of the addition should enhance the whole property.

Try and establish a ceiling price for your property in the local area as there will normally be a limit on how much your property will sell for.

Your feasibility study should provide you with an estimate of the cost for your proposal so you can check this is within your budget. The last thing you want is to end up with a superb design with planning permission only to find that all your builders quotations are twice your allowance. Most designers will find it helpful to know your budget so that they can design your loft conversion within it.

If your designer is unable to provide guidance on this, our section on Loft Conversion Costs provides lots of information on cost influences that you will need to consider.

We would always recommend that you allow a contingency (we would suggest 10-20%) for the unknown when working out your costs at the feasibility stage.

 

I. Planning and Other Approvals Considerations

Many loft conversions do not require planning permission (see our section on Planning Permission for Loft Conversions for further information on this).

However, if your proposal does require permission, make sure your designer is aware of any local planning policies that may restrict what you can build.

Have other properties on the same street been converted or changed from their original structure and are there any similar to your own? Your proposal may create a precedent for planning permission and this could cause the planners to look at the application more closely.

Our advice is for you or your designer to have an informal discussion with your local planning office prior to making any submission as they will normally be pleased to give you guidance that could save you time and hassle in the long run.

Also make sure you have considered any Building Regulations implications, Party Wall requirements and restrictive covenants that may impact on your design.

J. Storage

One of the disadvantages of converting your loft is that you will lose a lot of your existing storage space.

Whilst it may be a good opportunity to clear out some of your redundant possessions, you will undoubtedly still need some storage space after your loft has been converted. A good designer will consider this so make sure you try and gain as much space as you can.

K. Project Time Considerations

At the feasibility stage, we recommend that you give consideration to the overall time your project will take.

Do you have a set date that the work needs completing by? You may, for example, be planning to work from home at a certain time or you may have an imminent new arrival to the family.

This may, for example, dictate whether you include a dormer window in your design which will require planning permission and prolong the overall project time.

Our section on Project Timing covers this in more detail.