DIY Doctor

Insulating a loft with only 70mm high joists!!! Please Help!

Postby gihan » Wed Oct 22, 2008 8:48 am

Dear all,

I want to insulate the loft space in my 1890's built maisonette. I have read that current regulations state you should insulate to 270mm. Unfortunately the joists are currently only 70mm higher than the below ceiling.
I intend to place loft boards up there to use it as a storage area (maisonettes have very little storage room).
I have heard that you can fix batons along the original length of joists, but won't the extra weight of the batons[b]plus[/b] the loftboards [b]plus[/b] the general household stuff that i'll be storing up there, cause a weight issue to the celing below??
Please help as I'm only moderate DIY'er and have no idea of how much weight these old joists can hold.
I thank you kindly in advance for any replies received

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Postby welsh brickie » Sat Oct 25, 2008 7:31 am

you could use 50mm kingspan insulation or similar.
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Postby tileclipproman » Tue Jul 26, 2016 12:54 pm

the battons you fix along the existing joists will only strengthen the ceiling
not weaken it.
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Postby nhpendall » Sun Oct 09, 2016 6:41 am

you need to be careful about storing a lot of stuff in an 1890 loft space without first strengthening the roof/joists. have you got slates on the roof or concrete tiles ?. many originally slate roofed houses had their perfectly good slates removed as part of the mortgage conditions in the 1970's and replaced by inferior , and very heavy, concrete tiles. If this is the case then the roof is currently supporting much more weight than it was built for. to keep costs down the roofers tended to be very lax about re-inforcing the roof to take the extra weight. You can get steel legs that will support the loft boards above the 270mm insulation but keep the boarded area small and above supporting walls and do not store heavy items in the loft. Kingspan or Celotex will work and you can get it 70mm thick to match the joist size. it cuts easily with an old saw to fit between the joists. it is however quite expensive.
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