Floor insulation in loft conversion

Norman_Castle

beaker141 wrote: »

I put rockwool in my loft conversion floor joists, suspended on chicken wire.

I have very little sound transmission from the loft,

Did you suspend it so it touched the bottom of the floorboards?

I'm trying to stop noise, mainly tv and talking from a flat below me. How effective is your insulation against noise going up through the ceiling?

beaker141

Norman_Castle wrote: »

Did you suspend it so it touched the bottom of the floorboards?

I'm trying to stop noise, mainly tv and talking from a flat below me. How effective is your insulation against noise going up through the ceiling?

I dont think it did, I just stapled chicken wire in the void to make the basket, then laid Rockwool, from a guess it was probably 100mm. There is an air gap below, ie it doesnt touch the plasterboard ceiling underneath, and it may now touch the floorboard above through expanding out a bit but not by design.

If I'm in bed below the loft, I cant usually detect any noise from there from tv/xbox/conversation unless voices are raised.

XIX

Thanks for all the responses. Insulation was specified in the architects drawings - 100mm rockwool flexi supported by wire mesh. Currently there is absolutely nothing between the bedroom ceiling and the new floor joists and floor, I asked the builder why he hadn't followed the architects plan and he said the floor insulation wasn't needed as there would be enough in the roof and walls for warmth. He said he didn't think it would make any difference to noise traveling. He also said that building regs would sign it off without insulation in the floor.

I have said we'd like the Rockwool flexi installed but am worried they won't use the wire mesh - is this strictly needed?

Furts

XIX wrote: »

Thanks for all the responses. Insulation was specified in the architects drawings - 100mm rockwool flexi supported by wire mesh. Currently there is absolutely nothing between the bedroom ceiling and the new floor joists and floor, I asked the builder why he hadn't followed the architects plan and he said the floor insulation wasn't needed as there would be enough in the roof and walls for warmth. He said he didn't think it would make any difference to noise traveling. He also said that building regs would sign it off without insulation in the floor.

I have said we'd like the Rockwool flexi installed but am worried they won't use the wire mesh - is this strictly needed?

This is worrying. A builder who does not know basic Buildings Regulations. Or a builder who peddles nonsense to his client. Either way it is a warning signal that you need to watch your builder!

It is easy to say the work will be signed off because your builder will have been deceitful and hidden up the evidence of bodging. It is a certainty that had the Inspector asked if insulation was present your builder would have lied. Had he not lied the Inspector could say rip the ceilings down at the builders expense. A no brainer answer here!

But also face up to reality. It is your job, and your legal responsibility to deal with the Buildings Regulations and Inspections. If you allow your builder to hide defective work then you have to accept some blame here.

If the insulation was going to be missed out then what else is wrong with your work? What else has not been Inspected? What else has been covered up?

teneighty

XIX wrote: »

Thanks for all the responses. Insulation was specified in the architects drawings - 100mm rockwool flexi supported by wire mesh. Currently there is absolutely nothing between the bedroom ceiling and the new floor joists and floor, I asked the builder why he hadn't followed the architects plan and he said the floor insulation wasn't needed as there would be enough in the roof and walls for warmth. He said he didn't think it would make any difference to noise traveling. He also said that building regs would sign it off without insulation in the floor.

I have said we'd like the Rockwool flexi installed but am worried they won't use the wire mesh - is this strictly needed?

You don't need the wire mesh if it is for sound insulation, it just sits squeezed tightly between the floor joists laying on top of the ceiling. The wire mesh is more for fire proofing situations.

Your builder sounds like a bit of a cowboy, as Furts said, what else has he left out and hidden from the Building Control Officer?

I would go back over the work so far with a fine tooth comb.

XIX

Thanks for the advice guys. I'm definitely worried now, especially as I don't really know enough about building works to know if any other corners have been cut, especially structural ones - the insulation was an obvious one!

I'll get in touch with my building control officer tomorrow and see what he has to say

gazzak_2

Norman_Castle wrote: »

What has been done exactly? Old loft insulation left in place with more loft insulation or acoustic insulation on top?
Details would be appreciated as a flat dweller looking for cheap and successful solutions.

They simply put new insulation over the top of the old one to fill to the top of the joists. When a loft room is put in there are steel beams that go in so the floor is raised from the original loft beams anyway, so you have plenty of room, (LOL at the person above who said it would risk the ceilings on the floor below coming down).
The insulation was standard stuff as far as I could tell that came in 10 meter rolls and was 100mm in thickness.

gazzak_2

dunroving wrote: »

If you force too much insulation between the joists are you not risking the ceiling below?

As mentioned above, the steels raise the floor of the loft. Nothing is forced anywhere.

dunroving

gazzak wrote: »

As mentioned above, the steels raise the floor of the loft. Nothing is forced anywhere.

You clearly haven't seen some of the conversions up where I live.

Builder_Belsh

Have you had any fire proofing done? Often the reason for chicken wire and insulation is to give fire protection if the ceilings below have not been protected.