# how to increase attic space without increasing ridge height



## Brigid (28 Apr 2010)

Hi!  we have planning permission for a house which will have a large attic space but a ridge height at the 'collar' of only 5 feet and about 8 at the apex. We were considering contracting the house and seeing if we can increase the ridge height which would give us more space at hopefully a lower cost. We availed of the Simon Open Door initiative last week and met 3 architects who all gave us contrasting advice ... But it was excellent excercise and we have a clearer idea on how to progress. One architect suggested digging into the ground a foot or two to allow us keep the ridge height we have but to increase the head room in the attic.  we were thinking of stepping down into the property internally.  Another one has said he wouldn't recommend this as it isn't easy for it to work properly. He suggested getting a steel beam which would mean that we would have about 7 feet head room. We hope to meet the 'dissenting' architect later this week and I was wondering if someone could give me insight as to why the architects have disagreed on this matter.   We are not a flood risk and do have somewhere to dump the top soil taken.  Many thanks,


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## onq (28 Apr 2010)

Without seeing the plans its difficult to comment competently Brigid.
The first thing I 'd do is throw the question to you and ask where the ridge height limit arises.
Is it a site specific limit - to do with a view or a sight-line or an adjoining ridge - or can you seek a revised planning permission raising the ridge?

I'm not suggesting this to wind you up, I'm just asking, as part of a due diligence approach.
The reason being that it'll be a lot cheaper for you to redesign the house and seek a revised planning permission NOW, than jump through hoops on site sinking floors and building half-basements, which is where you're off to next I think.

8 [2.4M] feet internal ridge height works out to a total house width of 8.3 Metres front to back at a slope of 30 degrees.
At a 35 degree pitch this drops to 6.8M

This seems to be a narrow enough house depending on the pitch.
Thsi narrowness may adversely affect your bedroom planning especially if you want to have en-suites and the geometry of the stairs to the attic.

Also your ridge height seems to be aspirational in the sense you will need to deduct an increased depth of floor joist, floorboards and also the depth of HD insulation under the sloping roof joists, assuming you intend to convert this to well-insulated habitable space.

So my advice to you would be to consider the design of the house again with a view to allowing you a reasonable attic conversion.
Even small changes now could vastly improve the buildability of the whole thing later.

There are design based ways of vastly increasing the usable floor area.




ONQ.

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All advice on AAM is remote from the situation and cannot be relied upon       as a defence or support - in and of itself - should legal action  be      taken.
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## Brigid (29 Apr 2010)

Thank you - I know it is difficult to advise in the abstract.  The Ridge height from the ground outside is 8.22m.  The floor to ceiling downstairs is 2.70m and upstairs is 2.40m.   The angle of the roof is 40 degrees.  The width of the house down stairs is 8.45m and length  12.20m.  We were told that the ridge height that we got permission for is quite generous anyway and it is unlikely that we will get permission to increase it.  there are also 2 wings on either side of the main part of the house which are about 20sqm but a much lower ridge height.  We were going to delay building one of the wings anyway and maybe the second until we were in a healthier situation regarding funds.  I dont think that the 7 feet took into account insulation - not sure though. thanks.


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## onq (29 Apr 2010)

Hi Brigid,

My experience with Councils is that there are usually means of negotiating a better resolution through dialogue with Council Planners, once you have the primary permission, which you do.
You have to be clear on what you want and why you want it and then develop a design strategy that supports both your aims and the Councils stated objectives in their development plan.
In general the Councils are reasonable towards people who have permissions already - as long as they aren't going from, say, a three bedroom dormer bungalow to a Charlie McCreevy 6 bedroom mansion!

They might view that a little differently - or not! - you can only ask. 

The primary strategy these days must be based on affordability - you have to cut your cloth according to your measure.
The advantages of building elements of the building as roofs as opposed to walls is that they are cheaper to build.
Including a Gable feature at right angles to the main ridge will open up the roof space considerably.
Designing the roof space as Mansard may increase the usability of the space by as much as 50% again.

But you're then moving away from a relatively cost-effective build using timber to a more expensive composite build using a steel spider or more massive timbers, bearing onto strengthened walls and ring beam to reslove and transmit the loads etc.
And unless its very well designed and proportioned using tricks of traditional design and detail to mitigate the overall scale it may end up looking like like a very "heavy" 3 storey house, of which there still aren't too many in Ireland.

On your floor heights, a word of warning.
2.4M is the recommended minimum for habitalbe rooms, but this can get eaten into severely when you come to fit out.
Some people drawing up plans fail to allowfor the build up of floor covering and/or underfloor heating or even the thickness of plasterboard on the ceiling, both of which may act to reduce the height to 2.3 or below.
I generally specify floor to floor heights of circa 2.7M as a minimum and ensure that the joists don't exceed 225mm deep.
With floor covering of 25mm and 13mm skim plastering the overall depth is 263mm max. giving you a bit of comfort.

This isn't so much of an issue where you have the 2.7M head height obviously, but there you can end up with a different problem.
The stairs needs more or steeper treads to deal with the increased height and you have to ensure you have your clear widths, heights and treads as per Part K of the regulations.

Anyway, just a few small pointers to help you achieve your heart's desire.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon        as a defence or support - in and of itself - should legal action   be      taken.
Competent legal and building professionals should be asked to advise in        Real Life with rights to inspect and issue reports on the matters   at      hand.


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## Brigid (29 Apr 2010)

Thank you very much - The house is big enough as it is (especially with the wings) but it seems ridiculous to have a large attic area that cant be used for anything but storage. We are really only talking about an increase of head room in the attic space of about say 18 inches - I may try to give the planning office a call and see what happens. thanks again.


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## onq (29 Apr 2010)

You're very welcome.

Let us know how you get on.

ONQ

[broken link removed]


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## Brigid (30 Apr 2010)

Well I rang and spoke to the planner who said that the house was big as it was and since it was in a scenic area she really couldn't say whether or not permission would be granted for an increased ridge height... it is exactly as I expected.  She wasn't overly negative but I felt that she thought that I should be grateful for what we got!!  We don't really want to go back to the drawing board so I think we will be exploring the idea of sinking the inside of the house a little bit anyway.  We will have to talk to the architect and evalulate the challanges he has flagged and see how we should proceed.  by the way what are the challanges with sinking the floor area by a foot?


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## onq (30 Apr 2010)

If you build right up to the house you may need to tank the walls [very expensive] and if its timber frame you'll probably interfere with the below-DPC ventilation.

One possible solution is to reduce drop the the ground level outside the house to 150mm below the DPC level for the width of say a path - 1000mm or 3'4" approx. which is a drop of 450mm or 1'6".

This creates a kind of "area" like you see in older Georgian houses with the half basement and you have to make sure you can drain this area to avoid it flooding.

I'm always wary of situations like this so take your architect's advice regarding the specific site conditions involved and make sure there are at least two suface water drains serving the reduced level.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon         as a defence or support - in and of itself - should legal action    be      taken.
Competent legal and building professionals should be asked to advise in         Real Life with rights to inspect and issue reports on the matters    at      hand.


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## Brigid (30 Apr 2010)

thank you for this.  I appreciate that this is may be seen as an unfair question given your much appreciated observations, but would this be an area in which an engineer may have greater expertise? I ask this question an ignorant and someone who is still trying to suss out where the subleties of the differences between architects and engineers lie.  Thank you.


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## onq (3 May 2010)

Hi Brigid,

Well done for asking the question.

The architect designs in terms of light, procession and relationship of  spaces, light and amenity, historical and contextual reference, "style", form and detailing.

Engineers are the other side of the coin in terms of design.
Engineers are trained to design structures or services or mechanical production facilities or large scale civil works.
Many offices are not set up to do small scale domestic work - the fees are too little.

We recommend that the client uses a structural engineer as well as our office to design a house at tender stage - this is designing the built work at a stage where the way things are supported plays an important part in the overall detailing.

Up until this stage the architect's knowledge of structures - which is acquired over the course of a five year full time course  and follow up CPD and experience - informs him of the possibilities.

He requests a structural proposal from the engineer, and if acceptable, works up his details based upon that. If not its a referral back to the engineer with comment and suggestion until a workable and economical solution is devised.

In a classical design team there will be input from a Quantity Surveyor on costing.
This was especially useful in the boom times to stop builders fleecing the clients or to at least alert the client when they were being fleeced and by how much.

Now its to gauge by how much the builder is undercutting his break even point to maintain some turnover, and what the likelihood is of him going bust because of trading below cost in the middle do the job.

The knowledge of Quantity Surveyors of the available builders and the status of the companies make them even more useful now I feel, but you didn't ask this question.

Finally, if you are going for a hi-tech heat reclamation system or heating system, consider at least getting the specification written by an Mechanical & Electrical Engineer and asking him to assess the layout of the supply and extract air ducts to avoid short circulation and maintain fire separation.

They will also advise on the size of the wood pellet store if you're using one - they can spontaneously combust in an Irish climate - believe it or not.

This might sound over the top if you're the kind of person whose trying to balance the cost of professional fees against whether or not you can afford an AGA - many people seem to make this decision in favour of the AGA. 

The fact is that there is so much to do to build even a simple house well these days that you need to take good advice.

Traditional contractors, unless they've gone on courses to upskill themselves or are sub-contracting to companies deploying the latest construction methods including high levels of insulation, sealing and weather proofing may simply not be up to the task.

There is a wealth of detail on the Department of Environment and Health and Safety Websites informing laypersons of the obligations under the law in relation to both Health and Safety issues and Building Standards.

These key posts may be of assistance to you:

_The Self Build FAQ:_
http://www.askaboutmoney.com/showthread.php?t=126261

_What to ask and architect at our first meeting:_
http://www.askaboutmoney.com/showthread.php?t=131450

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon          as a defence or support - in and of itself - should legal  action    be      taken.
Competent legal and building professionals should be asked to advise in          Real Life with rights to inspect and issue reports on the  matters    at      hand.


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## Brigid (3 May 2010)

Many thanks. I know that you said somewhere in some post that more junior (or younger(!?)) architects than you studied a different curriculum which, from what i remember, would have had less of a structural input. That is why I am wondering if the concept of digging into the ground to achieve more of an attic space woudl be something that an engineer would know more about if the architect is relatively junior. To be honest if it poses serious difficulties I think we will give it a miss. It comes to a point when we have to realise that we have a limited budget and can't have everything!! 

We will definitely be getting an architect on board initally to draw up the specs or details which we are then going to give builders/trades people to see how much it will all cost, and then we will probably revisit the specs to see what we can change to keep the mortgage as low as possible. 

Unless they are way off the mark price wise we will probably use our neighbours who are general builders to do what ever they normally do. They are small builders who have been around forever and anything they would normally contract out, we will hire those people ourselves. this is partly to keep costs down and partly so that we will know the subbies ourselves and will know the quality of their work personally.


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## onq (3 May 2010)

Brigid said:


> Many thanks. I know that you said somewhere in some post that more junior (or younger(!?)) architects than you studied a different curriculum which, from what i remember, would have had less of a structural input.


Did I?
I seem to remember saying that things were different a while back and that unless your prospective builder is upskilled on new highly insulated forms of construction the house may not achieve compliance.


> That is why I am wondering if the concept of digging into the ground to achieve more of an attic space woudl be something that an engineer would know more about if the architect is relatively junior. To be honest if it poses serious difficulties I think we will give it a miss. It comes to a point when we have to realise that we have a limited budget and can't have everything!!


You're look like trying to get your head around this yourself with a professional advising you.
That's up to you but that's not how it works.
You'd be better advised to retain the professional and let them do their job and advise you fully before making a decision.
BTW I suggested lowering the ground and creating and Area for drainage purposes to avoid the cost and expense of tanking, not digging the house into the ground - that was your idea.


> We will definitely be getting an architect on board initally to draw up the specs or details which we are then going to give builders/trades people to see how much it will all cost, and then we will probably revisit the specs to see what we can change to keep the mortgage as low as possible.


With the greatest of respect Brigid, that would be a pointless exercise to carry out without your architect.
It normally runs - agree the spec, check the price, revise the spec, check the look - and do it again until its right.
Agree the lowest spec with your architect and see what design abilities he can use to make the place look a million dollars - that's what you pay a designer for.
Request him to perform a buildability and sourcing exercise with the Contractors and Sub-Contractors to reduce costs and find economies.
Do not cherry pick his ideas and "looks" and then try to do them on the cheap yourself - that's best left to an qualified designer.


> Unless they are way off the mark price wise we will probably use our neighbours who are general builders to do what ever they normally do. They are small builders who have been around forever and anything they would normally contract out, we will hire those people ourselves. this is partly to keep costs down and partly so that we will know the subbies ourselves and will know the quality of their work personally.


Small builders "who have been around for ever" are precisely the kind of people I am warning you about, without prejudice to these particular contractors.
If you're going to appoint an architect, my best advice is brief him fully and let him do his job, which is to deliver the best cost-benefits for you in this case.
He will assess all prospective contractors as well as their standard of workmanship.

Working with less expensive, less durable materials is an art in itself and one which your prospective builders may not have mastered.
He will - if he is competent - strongly suggest you do not limit your options by stating you prefer a contractor merely because you happen know him.
He will advise you to seek alternative quotations for the work because these are needed for many reasons not simply to establish a good price, but also to have fall-back positions should the preferred builder fail to deliver, go bust or pass away during the job.

TBH, you're beginning to sound as if you're not going to use a professional at all Brigid.
You're going to put your faith in a neighbour who is a builder.
What happens if things go wrong on site?

Beholden to a neighbour, your professionals unable to act to their best ability because of a limited brief, no fall back builder - not a happy place to be.
You'll also end up carrying the can for any design faults if you change things on site and didn't have them assessed by your designers.
Over to you Brigid and best of luck.

FWIW

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon           as a defence or support - in and of itself - should legal   action    be      taken.
Competent legal and building professionals should be asked to advise in           Real Life with rights to inspect and issue reports on the   matters    at      hand.


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## Brigid (4 May 2010)

just very  briefly as the more I write, the less well I seem to explain myself.  we will definitely be getting an architect to advise on specs and maybe the same architect to supervise the building.  We will not be blindly putting our trust in the builders - that is why we want professionals on board.  I think that the fact that they have been around 'forever' is in their favour. They stuck it out during the hard times in the 80's, didnt loose their heads during the boom, and are still small builders not 'developers'.

We will at all times take advice of the architect or engineer with regard to materials and workmanship etc. it would be really stupid to do otherwise. that is one of the reasons we wanted to wait to get a good architect or engineer - not just one from the Golden Pages - we wanted someone who was recommended and that was impossible to get!  We also wanted one that we felt we could get along with. We have now met with 3 architects and hopefully can move forward with one whom we hope to meet tomorrow, all going well.

thanks for all your advice. I am sorry that I didnt make myself clear above. with regard to a comment about the syllabus being different now,  I was referring to another thread where I thought you mentioned something like this. I could be wrong though.


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## onq (4 May 2010)

You may not be wrong Brigid, I just cannot recall it at the moment.

I'm heading towards 1,700 posts at the moment (and that's just on this forum) so perhaps I might be forgiven.

RE the "small builders who've been around forever" and tying yourself to that one builder - I rest my case: you pays your money and you makes your choice.

Best of luck.



ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon           as a defence or support - in and of itself - should legal   action    be      taken.
Competent legal and building professionals should be asked to advise in           Real Life with rights to inspect and issue reports on the   matters    at      hand.


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