Raks

suspended floor insulation advice please

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I would like to insulate the floor of a bungalow. Its suspended floor with 38x128 mm joists. The void is about 30cm.

If I would like to put 75mm kingspans between joist, whats the easiest way to fix them?

(batten each joist sides seems a lot of work)

And another concern is the rodents. How can I protect the insulation being chewed by mouse?

(there was a lot of advice not to use plastic pipes in void areas for this reason on an other tread!)

  

or is there any better way to insulate without compromising the air circulation of the void area and without rising the floor level.

Edited by Raks

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10 minutes ago, Raks said:

If I would like to put 75mm kingspans between joist, whats the easiest way to fix them?

(batten each joist sides seems a lot of work)

 

Nails partially driven in the sides of each joist at intervals - simply support the Kingspan on the projecting nails.

 

The mice will get sick of the taste of polyisocyanurate long before they have any noticeable impact , I think.

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I have done this from underneath and just did 10cm long battens at the joints of two board and the centre of each board.

I also pre drilled and inserted the screws in the hole so it was easy to install at ackward angles. 

are lifting the whole floor?

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if PIR is correct tight  fit it won,t take much to hold it up --

if not tight fit then it will let heat out  and cold in through the gaps at the sides  

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51 minutes ago, Moonshine said:

I have done this from underneath and just did 10cm long battens at the joints of two board and the centre of each board.

I also pre drilled and inserted the screws in the hole so it was easy to install at ackward angles. 

are lifting the whole floor?

Yes I am considering to remove whole floor of the house (around 90m2)

Is there any other way? (the void is 30cm so not enough space to work from underneath)

 

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38 minutes ago, scottishjohn said:

if PIR is correct tight  fit it won,t take much to hold it up --

if not tight fit then it will let heat out  and cold in through the gaps at the sides  

if the joist are straight and cut the insulation board a bit angled that fit  gets tighter when pushed between the joists,  would that be enough to keep the insulation safe in all weathers and  in the future? 

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In a similar situation I used rockwool attached with a staple gun, taking care not to go below the joist level. Saves a lot of time compared to PIR.

 

I then put a membrane and 25mm of PIR on top then a floating floor.

 

Ferdinand

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6 hours ago, Raks said:

Yes I am considering to remove whole floor of the house (around 90m2)

Is there any other way? (the void is 30cm so not enough space to work from underneath)

 

 

I lifted a few floor boards and found the underfloor void was 35-40cm, which was enough. However I was trying not to make too much mess in the room above. Taking floor boards up would have been easier.

 

There is a decent guide to it here

 

https://great-home.co.uk/underfloor-insulation-of-suspended-timber-floors/

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7 hours ago, Raks said:

if the joist are straight and cut the insulation board a bit angled that fit  gets tighter when pushed between the joists, 

good luck with that .LOL

unless they fitted dwangs between them 

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8 hours ago, scottishjohn said:

if not tight fit then it will let heat out  and cold in through the gaps at the sides  

 

A bead of squirty foam down each edge sorts the worst of this.

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