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Your loft conversion questions answered
Here we provide detailed answers to some of the more frequently asked questions about loft conversions. To assist you, beside each of the questions there is a ‘read-more’ link where you will find the answer and at the end of each answer there is a ‘back to questions’ link which takes you back to the list of questions.
Here is a list of the questions which are answered here:
- Is my loft space suitable for conversion? – read more
- Where will the stairs go? – read more
- How much will it cost? – read more
- How long will it take for the works to be done? – read more
- How long is it before the works can start? – read more
- Do I need Planning Permission? – read more
- I won’t need Planning Permission but can the Council confirm this for when I come to sell? – read more
- What are the Building Regulations? – read more
- I’ve heard about the Party Wall Act but don’t know if it applies? – read more
- What about rooflights – can I have these on the front elevation without planning permission? – read more
- Someone has told me that I need planning permission to change my hipped roof to a gable roof? – read more
- What can Ely Design Group do for me? – read more
Is my loft space suitable for conversion?
There are a number of parts to the answer to this question and some will be covered in subsequent questions/answers. The things to be considered, and I will elaborate on each of them below, are:-
- Headroom in the loft – is there already sufficient headroom or will the ridge need to be raised (subject to Planning) or can the ceiling below be lowered?
- Where will the stairs go – is there space above the existing stairs or will space need to be taken from one of the existing rooms.
- Headroom above the stairs – can the requirements of the Building Regulations for headroom above the stairs be met within the shape of the roof or will a dormer window be required?
- Is a dormer necessary to create the required amount of floor space up in the new loft?
- A friend has told me that you can’t convert a loft where there are modern trusses.
Headroom in the loft.
Ideally the more headroom (the vertical distance between the top of the ceiling joists to the room below and the top of the ridge board / trusses) that is already available the easier the solution for the conversion. In terms of a guide we would suggest that the distance needs to be at least 2.4m. Once the new structure is in place then the available finished height internally will be in the order of 2.1m. Clearly if the starting height is more than 2.4m then the finished available height will exceed 2.1m.
If the available height is less than 2.4m then it will probably be necessary to either raise the ridge level or lower the ceiling level in the rooms beneath. Raising the ridge will require Planning Permission and the chances of obtaining Permission will depend on the Planning Policies and whether nearby properties have had the ridge level raised. This is particularly important in terraced properties in Conservation Areas – if a row of say 10 properties in a Conservation Area all have the same ridge height then this will be far more difficult to justify (and therefore obtain Permission) than where say four of the ten properties have raised the ridge level and each are of a slightly different height. The other consideration with Planning permission is the three month delay to a project and the associated uncertainty of whether Permission will be granted.
The alternative is to lower the ceilings to the rooms beneath. Clearly this will cause far more disruption to your home and may not be acceptable if you have already decorated/finished these rooms. If the loft is part of a refurbishment project that involves new ceilings, plastering walls etc. then this solution may be the best way forward. Providing there would still be about 150mm above the windows for curtain rails, architraves etc. then lowering the ceiling is a good option.
Where will the stairs go?
Ideally we would always try to position the new stairs above the existing stairs. This is not always possible due to the configuration of the first floor landing and doors into the various first floor rooms. Sometimes it will be necessary to move walls and doors slightly so that the stairs can be accommodated above the existing stairs.
Where stairs need to be put into one of the first floor rooms it is key to consider whether or not the benefit of gaining the loft space is outweighed by losing an existing room together with the cost and disruption associated with the building works.
Headroom above the stairs
The Building Regulations require that there are minimum distances above the new and the existing stairs. 2.0m must be maintained above the pitch-line of the stairs (the pitch-line is a notional line joining the fronts of each of the treads and the headroom is measured vertically above this line). We would design for 2.1m so that there is an allowance for finishes and on-site changes that the Builder/Joiner may choose to make. At least 1.9m is required above the middle of the pitch-line of the new stairs and 1.8 above the string or side of the stairs. Again we would design for 2.0m and 1.9m respectively.
These requirements then influence where the stairs will go and also whether a dormer window is required.
Is a dormer window required?
A dormer is normally required for one of two reasons. The first is to enable the headroom requirements above the stairs to be met and the second is to create more full-height usable floor space within the loft.
The popular solution is the rear-facing flat-roofed box dormer which spans the full width of the rear elevation of the property. Whilst this is not the most architecturally attractive dormer it does transform the amount of usable space. There are many materials that can be used including lead, slate and natural and manufactured boarding. These dormers are normally timber framed construction and are well insulated.
Of course other dormer styles and sizes can be designed to meet your requirements providing that the Building Regulation requirements can be met.
There is no reason why roofs constructed using modern manufactured trusses cannot be converted particularly where the external walls are of masonry construction. If your property is timber framed then again the conversion should be possible although this becomes more of a matter for a Structural Engineer to prove that the timber frame itself can accommodate the additional loads, alterations etc.
It is likely that steel beams will be required to support the new floor joists which in turn will support the existing rafters.
Once the new structure in in place then the Builder can remove the diagonal struts typical of the modern trusses.
How much will it cost?
Cost is one of those ‘chicken and egg’ questions!
Sometimes Clients want to know the cost before they are willing to start with the design stage of the process but a certain amount of design work needs to be done so that the degree of difficulty to convert the loft is understood together with the Client’s requirements so the Builders can give even a budget estimate for the loft conversion.
As a guide loft conversions can range from £40,000 to £130,000 +
Even at the initial meeting we will gain an appreciation of the complexity of the solution and may be able to suggest the likely cost. It is often worth considering what your budget is.
We suggest that once the design is agreed and ready for submission for Planning Permission, if this is applicable, that two builders who are experienced in loft conversions are invited to provide a budget estimate for the works. They won’t know the exact steel sizes, thickness of insulation and design of the stairs, for example, but will be able to provide you with a +/- £5,000 estimate for the works. This will enable you to proceed with the peace of mind that the project will fit your budget; if the cost exceeds your budget then we can look at solutions to reduce the cost of the works.
How long will it take to do the works?
Most loft conversions, and I am generalising here, will take in the region of 3-4 months.
Clearly the amount of time will depend on the size and complexity of the project. In addition access to the loft will have an effect on the time taken, along with if you are going to occupy your property during the period of the works, the time of year and even the size of the building company you choose to employ to do the works.
How long is it before the works can start?
The amount of time before works can start will depend on a number of issues including
- If planning permission required
- How long will it take for the design to be prepared, amended (if necessary) and then approved by you as the client
- If the Party Wall etc. Act 1996 apply, how your neighbours respond to the notices and the likely time to get the Award in place
- If you want to obtain tenders for the works or if you have already got your builder ‘lined-up’
- When can the builder start
- The time of year – will you want to uncover the roof in January for example?
So there are lots of ifs, buts and maybes! However if I give you the two extremes then maybe you can gauge where your project fits and estimate the time.
The first scenario is a loft conversion to a detached house or bungalow that does not need Planning Permission and the Builder is lined up and ready to start. The design period (depending on our work commitments at the time) including the measured survey, preparation of existing plans and elevations, the design and the amendments to the design is likely to take approximately a month. Once you have approved the design the working drawings, obtaining the Engineers details, Building Regulation Application and Approval period will likely take up to a four to six weeks. The Builder could then start. This gives a total of approximately eight to ten weeks.
The second scenario is a loft conversion to a mid-terraced house in a conservation area which involved works to both party walls and you would like to obtain tenders from a selection of Builders. The design period (depending on our work commitments at the time) including the measured survey, preparation of existing plans and elevations, the design and amendments to the design is likely to take approximately a month as with the first scenario. Once you have approved the design we would submit the Planning Application – the approval period (assuming that Planning Permission will be granted) will take approximately ten weeks. Upon receipt of the Planning Permission we prepare the working drawings, obtaining the Engineers details, Building Regulation Application and approval period will likely take up to a four to six weeks. We would also prepare and serve the Party Wall Notices. Depending on how the neighbours respond to the Notices defines how long this part of the process will take – likely to be 4 weeks or so. Once the Building Regulation Application has been submitted we would prepare the tender documentation (allow two weeks), invite tenders (allow three weeks) and upon receipt of the tenders prepare the tender report. The Builder could then start but the actual start date would depend on their availability. This gives a total of approximately five to six months plus the Builders lead in time.
So in answer to your question, the amount of time will be somewhere between 2 and 6 months + the Builder’s lead-in period from the date when we receive instructions to proceed to the builder actually starting work on site.
Will I need Planning Permission?
‘It depends’ is the answer. Below is a link to the list of criteria that need to be satisfied for a loft conversion to be allowed under the ‘permitted development’ rules.
It is likely that if your property is in a Conservation Area, a listed building or a newer property where the permitted development rights have been removed then Planning Permission will be required.
I won’t need Planning Permission but can the Council confirm this for when I come to sell.
If you have established that according to the rules for permitted development, your loft conversion does not need Planning Permission but you are keen to ensure that when you come to sell your property there are no delays to the sale whilst Solicitors argue over whether Permission should have been obtained then, in this situation you, or Ely Design Group on your behalf, can submit an application for a Certificate of Lawful Development to the local Planning Authority.
The application form requires you to explain why the development is lawful, i.e. it is permitted development, and we would normally make reference to the permitted development rules referred to above. The application will be accompanied by the drawings (existing and proposed) and the application fee which is half the cost of the Planning Application fee for a Householder Planning Application.
The application will be decided by the Council and, providing the proposed development is permitted development, the Certificate of Lawful Development will be issued.This Certificate should be kept in a safe place and given to your Solicitor when you come to move.
What are the Building Regulations?
The Building Regulations are the set of ‘how-to-build’ rules which need to be complied with in order to meet the requirements of the Building Act. The Building Act is explained in a series of ‘Approved Documents’ which cover aspects such as structure, means of escape, drainage, conservation of heat and power, access, ventilation etc.
There are two approaches to comply with the building regulations (regs) and these are ‘Full-Plans’ or ‘Building Notice.’
The Full Plans process is to submit an Application to a Local Authority’s Building Control Department or an Approved Inspector (private company). The application will be accompanied by the application fee, drawings, construction notes, Engineers’ details etc. The Building Control Department will allocate the application to an officer who will check the details and write to you or your agent (Ely Design Group) with details of any further information they need. Your Designer will address these queries and the Council will issue a Notice of Passing of Plans. Sometimes this is conditional if further information, typically the Engineer’s details, are still being checked. Once the details are submitted to address the conditions the Council will issue the unconditional Notice of Passing of Plans.
The second route is the Building Notice. Again an application is submitted to the Local Council and accompanied by the application fee only. The Council can request any further information and this may include drawings, Engineer’s details etc. but the onus is on you/your Builder knowing how to build to comply with the Building Regulations. If, upon site inspection, something does not comply with the Building Regulations then this is up to you to resolve so that Building Control will be satisfied.
With either option inspections are carried out during the building process and, providing the works are carried out to the satisfaction of the Building Control Officer a Completion Certificate will be issued and again this needs to be kept safe for when you come to sell your home.
A similar process (Full Plans route only) applies when the Building Control service is being provided by a private company in terms of application, fee, checking the details, asking for further information and site inspections together with the completion certificate.
I’ve heard about the Party Wall Act but don’t know if it applies
The Party Wall etc. Act 1996 is legislation that allows you to exercise certain rights, in the context of loft conversions, to the party wall(s) between you and your neighbour(s). For example you can raise the full thickness of the party wall to form the side of your dormer, cut into the party wall to support beams, remove chimney breasts on your half of the wall and other similar activities that will enhance your loft conversion and add to the available space.
The process to exercise these rights is to serve Notice under the relevant section (Section 2 for works to the party wall) on your neighbour(s) giving them the details of the notifiable works. You can serve these Notices yourself but make sure there are no errors! If the neighbour consents to the works then there are no further requirements under the Act. Some neighbours will agree subject to conditions such as insurances and/or a Schedule of Condition; a Schedule of Condition is a written and photographic record of the condition of the neighbour’s property before the works start. The benefit of having the Schedule in place is that it is easier to prove (and disprove) a claim for damage.
If the neighbour dissents to the Notice or does not reply within fourteen days (and a further ten days when a response is requested) there is a dispute. In the event of a dispute each side must appoint a surveyor or agree to appoint one Surveyor who will act as the Agreed Surveyor. The two Surveyors will agree on how to resolve the dispute and their agreement is documented in a Party Wall Award; the Award will also contain a Schedule of Condition in almost all instances.
There are other aspects of the Party Wall etc. Act 1996 which we would be pleased to explain but, for most domestic loft conversions, this summarises the normal course of events.
Some neighbours see the Act as another method of being able to delay the process and cause you to incur additional costs. However the Act is an enabling act with strict timescales built in so that the process continues.
In most instances you will pay your neighbour’s reasonable costs and these will include any reasonable surveyor’s fees that the neighbour incurs although costs, including fees, are one of the many matters that the Surveyors decide on.
What about rooflights – can I have these on the front elevation without Planning Permission?
Planning Permission is not normally required to install rooflights as this is another part of the permitted development allowances. The rules are listed below and providing you comply then you do not need to apply for Permission. Again you can apply for the Certificate of Lawful Development we mentioned before if you would like this peace of mind.
- they do not protrude more than 150mm beyond the plane of the roof slope
- they are no higher than the highest part of the roof
- if they are in side elevation roof slope they must be obscure-glazed and either non opening or more than 1.7 metres above the floor level
If you live in a listed building or designated area (conservation area, national park, area of outstanding natural beauty, etc…) you should check with your Local Planning Authority before carrying out any work.
Someone has told me that I need Planning Permission to change my hipped roof to a gable roof
We have designed a number of loft conversions where hipped roofs have been changed to gables so that the box dormer can be provided across the rear elevation.
Recently we were asked ‘were we sure as another Architect has said that Planning Permission WAS required for a prospective clients loft conversion.’
There are a number of criteria that need to be met in order for a loft conversion to be considered to be permitted development
- A volume allowance of 40 cubic metres additional roof space for terraced houses (including any previous roof extensions)
- A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses (including any previous roof extensions)
- No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway
- No extension to be higher than the highest part of the roof
- Materials to be similar in appearance to the existing house
- No verandas, balconies or raised platforms
- Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor
- Roof extensions not to be permitted development in designated areas – designated areas include National Parks and the Broads, Areas of Outstanding Natural Beauty, Conservation Areas and World Heritage Sites
- Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves
- The roof enlargement cannot overhang the outer face of the wall of the original house
- Permitted development rights have not been removed
We spent some time searching the various Councils’ websites and there are numerous examples of Certificates of Lawful Development being issued throughout the country.
We can confirm that Planning Permission for hipped to gable loft conversions is not required subject to the above mentioned criteria being met.
What can Ely Design Group do for me?
Ely Design Group can help you through the various statutory approval stages of the process and assist you during the construction phase of your project. Following the initial site meeting we will write to confirm our services and the associated professional fees. Our services are normally divided into six stages as follows:-
Stage 1 A full measured survey of your property and preparation of drawing(s) showing the existing plans and elevations
Stage 2 Preparation of sketch plans (the design drawing(s) which we will send to you for your comments and/or approval. Planning Application / Certificate of Lawful Development. Obtain budget estimates if required
Stage 3 Preparations of working drawings and construction notes. Submit the application for Building Regulation Approval and deal with queries in order to obtain (Conditional) Building Regulation Notice of Passing of Plans. Obtain fee proposal from the Engineer and liaise with the Engineer.
Stage 4 Serve Notice under the Party Wall etc. Act 1996 and, in the event of a dispute, act as your Party Wall Surveyor or the Agreed Surveyor if your neighbour agrees
Stage 5 Prepare a detailed schedule of works describing the works and obtain tenders from selected Building Contractors. Upon receipt of the tenders to prepare a tender report with recommendations as to the choice of the Contractor for the works
Stage 6 To visit site on a regular basis to check that the works are being carried out correctly in accordance with the drawings, specification and the Building Regulations and to a reasonable standard of workmanship. We will agree monthly valuations with the Contractor and certify amounts due under the contract and issue instructions for variations. At the end of the project we will issue a snagging list for the contract or to address and repeat this process again after six months
Whatever stages you instruct us to carry out we are available to answer your questions about any aspect of the pre- and post-contract stages