internal walls, heat loss?? puzzled

johnpawl

I cant get my head round this point...there's big emphasis placed on preventing heat from the inner leaf and the concrete floor being drawn down to foundation through cold bridging...solutions include quinn lite blocks on lower block courses and floor insulation returned up along the perimeter of the floor slab..ok, all this makes perfect sense to me.. What I cant understand are the internal block walls which are meshed in with the inner leaf...these block walls extend straight down to the foundation and the floor slab is not insulated from them... surely these are acting as a cold bridge?
I'm thinking that people might say that this is neglible further in on the footprint of the house.. but what about the junction between these walls and the inner leaf of the exterior walls? I mean just because you're 50mm in along the internal wall doesnt mean it'll be acting any differently than the inner leaf?? Whats the story?

sinnerboy

Your head is not letting you down - your observation is sound .

Internal block walls should be treated in the same way as the inner leaf of external walls i.e. a thermal break should be installed between them and the ground .

However I would give serious consideration to using an insulated foundation which would address the issue for all walls .

Google "insulated foundation systems"

johnpawl

sinnerboy wrote: »

Your head is not letting you down - your observation is sound .

Internal block walls should be treated in the same way as the inner leaf of external walls i.e. a thermal break should be installed between them and the ground .

However I would give serious consideration to using an insulated foundation which would address the issue for all walls .

Google "insulated foundation systems"

Hey Sinnerboy, thanks for reply.. Checked out that insulated foundation and found a couple of companies....My gut feeling would be that it'd be fairly pricy but I'm going to ring during the week to see whats the craic...Would a row of quinn lites all round just under dpc do the trick or is there an issue with these getting wet? Thanks..

sinnerboy

The denser QL's can be used below DPC . They are not affected structurally but they are affected thermally i.e. they become less insulative . So use them from the footing up .

johnpawl

sinnerboy wrote: »

The denser QL's can be used below DPC . They are not affected structurally but they are affected thermally i.e. they become less insulative . So use them from the footing up .

Would I be right not to use them above dpc because joint where they meet normal blocks will cause plaster cracking??

sinnerboy

If you use them above DPC - use them throughout - ( to avoid cracking )

Mellor

A solution a detailed a few years ago (as a student too mind you!!!) used foamed glass blocks as a break between the foundations and the first warm block course. The cost per block is higher than normal, but remember you the gain is a lot higher than quinnlite or similar.

I was fobbed off by some of the older lecturers as being over critical of that junction. I guess time has proved me right.