Hi All,

Happy New Year!

I have been lurking here for a good while now, but have now joined up, as building works are a lot more imminent!

I am extending / part re-furbishing a Scottish Steading.

All the new, and part of the old will be built well beyond current building regs in terms of air tightness, insulation, triple glazing, etc etc.

However, due to financial constraints and other issues, i am not able to fully upgrade all of the older part of the building to my preferred level.
The new area is all underfloor heating, but the old (just bedrooms, so never more than 16 - 17 degrees) is served by conventional radiators.
I am insulating and draft proofing beneath the existing floors in all but one room, and will be replacing all the existing central heating pipe runs and solving all the fit sized holes in the floor.

so, question,
do i lay the new central heating pipes above the insulation quilt and breather membrane in notches in the joists, through the insulation in holes through the joists, or well lagged and underneath the whole lot?

My brain suggests they should be above all the insulation to ensure any heat loss makes it into the house rather than the floor void.

I have read numerous threads about insulating and draft proofing floors, but cant find reference to pipe-zones.

thanks!

The Doctor

thanks - my thoughts too.

joists are big enough, and mostly across a corridor, so only 1100 long anyway!, and notches will be between 10 & 25% from ends, as specified.

This is clearly easier with a quilt insulation, and a pain with board insulation. I am unlikely to go as far as a wool insulation. What would you recomend?


from a green point of view, i'm assuming copper over plastic? or am i wrong?
both are from a finite source, both require lots of energy to make, and both are recyclable! Is this an issue?!

Hi

the 'whole house book' suggests polybutylene for hot and cold and polyethylene for underground service
copper comes third after steel
though I'm unsure if this is the up to date thinking

I use the speedfit range as its labour saving , less joints required , easily reusable demountable fitting
I had one joint fail in the last 5 years , which you might expect from copper
and it made up the road from my house


they make a polybutylene for the underfloor heating pipe which can be used for H and C

joists are 225mm

no sleeper walls - notched into existing stone walls
apart from short lengths, the majority of the pipe runs follow a long corridor, with only short intrusion into rooms to the radiators, and all of these intrusions, bar one, follow the joist line, so i'm laughing.

will go for plastic - my preference, just unsure of their green credentials - relative to alternatives.

Mike
is strawberry mesh a good (cheaper) alternative to breathable felt
ie draught proof yet breathable

Jim

It will be far more important to be air sealed between the room and under the floor than either of the other two things.

Have you seen this thread? http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=772&page=2#Item_3

A big culprit for wind getting in is under/behind skirtings. How do you propose to stop them?

skirtings are coming off throughout. they are very poorly fitted mdf cr*p.
external wall plaster on 600mm thick sanstone (largely bossed) is coming off, so i have full control over this junction where i am carrying out this exercise.

internal wall plaster is wet plaster to brick and either being replaced, removed to expose brick, or retained.

largely speaking, i am taking these areas back to basics, so not having to chase earlier faults to ground.

ANYTHING is better than the current floor where i can push my fingers through up to the knuckles in at least 3 places!

I did a very quick calculation on the floor alone, and estimate (conservatively) that the current open area of the floor to the solum is somewhere in the region of 0.3 sqm. Alternatively known as a barn door!

having read here for a while, i am learning the importance of air leakage!