Help Needed: Filling a cavity and insulation of crawlspace questions.

pathogan2008

Hi folks,
I'm hoping some of you can advise me here, as I'm new to this.

The room circled in red in the plans (pic 1 & 2) is significantly colder than the
rest of the house.
With winter approacing I want to rectify this.
I investigated the crawl-space/attic over this room today.
There is 100mm fibreglass insulation between the joists (pic 3)
There is 100mm insulation wrapped around the velux window plasterboard boxing to the
room below (pic 4ab)
There is an open cavity (pic 5) between the walls of family room and the (unheated) store & utility - shown as a blue line in the plan (pic 2)

What is the best way to proceed with making this room warmer?
I assume this cavity can/should be filled? Can I do this myself? If so, what
material should be used and where can I get it?
Any other tips on improving the insulation greatly appreciated.

Poor Uncle Tom

Start by filling the cavity and adding another 200mm of quilt in the attic space. In this case the cavity could be pumped but it will probably need to have a closer fitted, in this case a WBP plywood closer would work best.

pathogan2008

Thanks for you reply Poor Uncle Tom.

What material should be used to fill this cavity?
would Warmfill bonded bead type material be ok?

I'm not too familiar with cavity closers.
Are these the ones? Can they be picked up in any builders providers?

http://www.building-supplies-online.co.uk/cavity-closers-33-c.asp

What is the purpose of the closer? Would I then run the 300mm quilt over the closer?

As for the Velux skylight box, should I just increase the insulation on this to 300mm also? Is there a better way to improve heat loss here. I always felt that this was one of the problems losing heat in the room.

Thanks, PH.

Poor Uncle Tom

pathogan2008 wrote: »

What material should be used to fill this cavity?
would Warmfill bonded bead type material be ok?

Yes, any pumped bead would do.

pathogan2008 wrote: »

I'm not too familiar with cavity closers.
Are these the ones? Can they be picked up in any builders providers?

http://www.building-supplies-online.co.uk/cavity-closers-33-c.asp

Those are propriety cavity closers. A DIY version would be just as good. A strip of WBP plywood steel nailed to the blocks would do the job and shouldn't be anywhere near as expensive.

pathogan2008 wrote: »

What is the purpose of the closer?

It is presumed that the pumped bead would be under some pressure while being pumped. If the cavity is not closed the pumped bead will not be under any pressure and may not travel to fill all areas of the cavity.

pathogan2008 wrote: »

Would I then run the 300mm quilt over the closer?

Yes.

pathogan2008 wrote: »

As for the Velux skylight box, should I just increase the insulation on this to 300mm also?

Yes.

pathogan2008 wrote: »

Is there a better way to improve heat loss here. I always felt that this was one of the problems losing heat in the room.

Apart from removing the roof window and reinstating the flat ceiling, there isn't too much you can do apart from upping the surrounding insulations.

MicktheMan

pathogan2008 wrote: »

Thanks for you reply Poor Uncle Tom.

What material should be used to fill this cavity?
would Warmfill bonded bead type material be ok?

I'm not too familiar with cavity closers.
Are these the ones? Can they be picked up in any builders providers?

http://www.building-supplies-online.co.uk/cavity-closers-33-c.asp

What is the purpose of the closer? Would I then run the 300mm quilt over the closer?

As for the Velux skylight box, should I just increase the insulation on this to 300mm also? Is there a better way to improve heat loss here. I always felt that this was one of the problems losing heat in the room.

Thanks, PH.

Remember, heat loss through conduction (which good insulation addresses) is only half the heat loss story. Don't forget about good air tightness and ventilation. A simple air tightness test may help a lot in determining other major heat loss mechanisms.

pathogan2008

Thanks MicktheMan, Poor Uncle Tom,

My plan is to install the cavity closer, and fill the cavity with bonded bead.

When adding the new 200mm quilt, should I lay it parallel on top of the existing 100mm, or perpindicular across it, covering the joists?

Also MicktheMan, how would one go about doing a simple air tightness test?
(Sorry, I'm new to this?)

PH

MicktheMan

pathogan2008 wrote: »

Also MicktheMan, how would one go about doing a simple air tightness test?
(Sorry, I'm new to this?)

PH

The simplest (diy) test to do is to check for air movement around all juctions, fittings etc on a v windy day. By junctions, I mean wall to floor/ceiling, around all windows/external doors, around lights, sockets, where pipes etc enter the house from f.i. the attic, floor boards etc. a lit candle/cigerette can be used to check (with the obvious safety precautions taken).
Pros: cheap, can do yourself
Cons: lack of experience, inconsistant wind pressures on different sides of the house can give misleading results.

The professional way is to temporarily erect a large calibrated fan in the doorway and pressurise/depressurise the house and check/quantify leakage using various tools from trace smoke sticks to high resolution thermal imaging equipment. Also, the experience of the tester is v important in order to quantify & prioritise the findings and offer suitable recommendations taking building physics into account.
Hope this helps:)