Hi all,

Sorry if this is long winded but I want to get my explanation out for several questions that I have!

A while back I spoke about putting in storage space behind a wall in our house. The short story is that the house is built with the rear bedroom part in the roof. So the room has a sloping ceiling and then a small vertical wall. Behind this wall is the space that I would like to utilise. I have added a sketch which I hope helps to explain the current situation.

The previous issue about breaking through the stud work and if the studs in turn support the roof purlins has not turned out to be a problem because the roof is supported by an RSJ and the wall is apparently not load bearing. This wall consists of a sole plate and ceiling plate of 70mm x 47mm and studs of 70mm x 47mm x 860mm high with the studs 350/360mm apart from each other. I was thinking of a door into the storage of 700mm x 700mm just above the skirting so I do not need to get more carpet!

The available space is 1.2m by up to 4m (if I can sort the toilet overflow out as it goes through the middle of the available space).

Is there any reason why I should be careful before I precede any further – regulations etc?

The next problem that I am having in my mind is to do with making sure that the floor and roof are properly insulated and making sure that the floorboards are secure. Please see my sketch as it may explain better than me.

Roof - The roof is made up of tiles, air gap, felt and joists (35mm x 120mm). What I planned to do was to put battens on the inside of the joists to create a 45mm air gap, then 75mm Celotex (75mm would fit with 45mm air gap to make the 120mm depth of joist or do I go for 100mm Celotex and add wood to joists and reduce air gap as I was trying to get a near 50mm gap?), then air gap (using sections of wood to hold Celotex in place and to attach plaster board to) and then plasterboard.

Floor – the floor joists are the same as in the bedrooms, 45mm x depth unknown but over 100mm. Where the roof joists attach to the floor joists there are two joists one is 45mm thick and the other was 100mm thick with an inch gap in between (not sure why and if I can insulate inside?).

My problem was how to insulate and plaster into the corner so I was thinking of a small vertical stud wall (small uprights onto roof joists) which I can then leave the small inch gap as it is, add more insulation and then add plaster board. This causes me a problem of how to support the floor boards?? Do I put noggins at say 400mm centres in between the roof joists and then on top use a length of 100mm x 50mm on top of the noggins which I can then secure the floor boards to? The floor where the roof joins is so limited in height that I cannot see it being for heavy storage

I suppose my first question is are there any regulations to be mindful of

Second question is supporting the floor boards - is noggins at 400mm and a long section of 100mm x 50mm wood ok to support the floor?

Third is insulation, air gap/thickness - is 50mm air gap, 75mm celotec, 20mm air gap, plasterboard ok?

Thanks for reading and if there is any way to explain in less words please let me know!

Post edited to include pics (some people don't trust PDF's)

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Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

Just re-read this and trying to work out how to simplify the above an perhaps ask one question at a time.

First question, what is the best way to support floor boards in this storage area? I was thinking noggins between floor joists at say 400mm centres and a piece of 4x2 on top that runs the length that I can then screw the floor boards onto. Any comments?

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

How are you attaching the noggins?

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Mike
http://rebuildingatimberbungalow.blogspot.com/
any advice welcome

Hi Mike,

If noggins is the way to go, I was going to screw through into the floor joist or vice versa. The joists are 45mm x 200mmx 4000mm approx, if that helps? Not sure of size of noggin but maybe 3x2 or 4x2? Load would be minimal as roof height would be 120mm in that area.

Or do I ignore noggins and extend floor to where floor meets roof? Then not sure about the 1 inch gap that is there and insulating it.

Cheers

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

In a floor space (supporting) I would always use joist hangers to support the noggins. You will have a hell of a weight above that area with the sole plate of the roof

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Mike
http://rebuildingatimberbungalow.blogspot.com/
any advice welcome

Hi Mike, thanks for getting back to me. Joist hangers look the way to go, thanks Do you think that 400mm spacing of noggins is ok or can it be wider?

I have one question, what is the sole plate of the roof and why is there a lot of weight? Sorry if it is a dumb question.

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

400mm centres sounds good to me. With my little project I am doing 300mm centres because of the weight of the roof.
The sole plate is vitally important because its what your whole roof rests on

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Mike
http://rebuildingatimberbungalow.blogspot.com/
any advice welcome

I will stick with the 400mm centres then

I have seen the joist hangers and some attach to the side of the joists and others attach over the top and screw top and side, which is ok for my job do you think? I was thinking of over engineering and over the top!

The roof seems to sit on the 100mm thick joist (is this the sole plate?) that I am going no where near, plus it sits on an RSJ that is just above the wall of the storage. I did not want to go near the 100mm thick joist so I moved out to the 45mm floor joists.

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

I would get jiffy hangers that go go over the top - dont use screws on joist hangers - use twist nails

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Mike
http://rebuildingatimberbungalow.blogspot.com/
any advice welcome

Why would you not use screws, is there any particular reason? I only mentioned screws as I was told that hitting a nail might affect the plaster below?

Thanks Mike for all your help.

Now are you any good with insulation?!

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/

when you buy the joist hangers it will say on them that twist nails should only be used. I have had used screws/plugs but only where there is a mortar joints are dead sandy

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Mike
http://rebuildingatimberbungalow.blogspot.com/
any advice welcome

I looked at joist hangers last night and it did not mention twist nails but I will go out and look for some, is 30mm length ok?

Do you think that it will affect the plaster ceiling that is attached underneath hitting the nails in?

_________________
Nick

If UHM's helped then please check out UHM's Nominated charity - http://www.donnasdreamhouse.co.uk/