Cold Bridging and Insulation : the issues and solutions

metalscrubber

But you do make sense - I dont want to build a zero energy house but rather an economic as low energy as practical house.

Metal

ardara1

metalscrubber wrote: »

Excuse the simplistic nature of this question but just how big an issue is coldbridging in measurable terms ?

So I build the imposible house where each element, walls, windows, floor slab, roof, doors etc each have a Uvalue of 0.2

Using standard building techniques I end up with less than ideal, but not crummy thermal joints between these elements.

What does it do to th total Uvalue of the house ?

Or is this a how long is a piece of string ?

Metal

Hi MS -

If you go for the standard you're looking for and take a typical 3 bed semi, the HEATLOSS from the NON REPEATING thermal bridges at junctions will TYPICALLY be around 30 W/K for craappy detailing (min standards allowed under Part L) 16 W/K for better than those asked for in Part L - and approx 6 W/K for the standards being worked on for currently (Big change in details - but nothing over the top - basicallt lining of all junctions - no floor protrusion into inner skin of build)

In a well insulated house - such as that you're suggesting - can lose 1/3 of its faric heatloss thru bad detailing. This in its self is reason enough to improve things - but because we're building tighter - and the U-values are getting better the junctions are becomming more prone to moisture & mould. I've seen it happen even from the last revision in 2006 (Harwood floors going black at edges)

The draft Part L asks for big improvements - with an INSPECTION REGIME on site - but won't point you at any specific details - still working in them I suppose!

Your thermal bridging can be AND should be measured to make sure they can cope with the improvements else where in your design.

sinnerboy

"The draft Part L asks for big improvements - with an INSPECTION REGIME on site - but won't point you at any specific details - still working in them I suppose!"

Look here

http://www.planningportal.gov.uk/eng...314255826.html

Mellor

Cold bridges will have an effect of energy, and it brought up alot, especially in reference to new products.

Nobody mentions that building a one-off/detached house is loses alot of energy. I am talking about building form not construction energy or embodied energy btw

ardara1

sinnerboy wrote: »

"The draft Part L asks for big improvements - with an INSPECTION REGIME on site - but won't point you at any specific details - still working in them I suppose!"

Look here

http://www.planningportal.gov.uk/eng...314255826.html

The accreditted details you point to refer to the 2006 reveison of Part L Eng & Walers - they're being updated - we shoud have been following them from 2006! - now we've jumped further - the details need changed again!

Viking House

kadman wrote: »

Hi VH,

As far as I am aware the figures quoted are for polystyrene panels , not plastered panels. I do know for definite that our water absorption tests, for full immersion and partial immersion, are definitely polystyrene only. As well as all our tests for thermal conductivity, panel densities ect.
I,ll check for other results and tests which will clarify things further.

kadman

Hi Kadman/Mellor

An update here on Polysterene.

The EPS we used on our roof shelter did not have the Polysterene air pockets bonded well enough together and let the rain through, normally this would not happen so I stand corrected!

Aerobord said one other interesting thing in that they have moved away from the market that is looking to use EPS on a flat roof as an inverted roof on top of a layer of Bitumen. There was water getting in between the sheets of EPS onto the bitumen roof. The heat from the bitumen evaporated the water and caused the EPS to get damp. The evaporating water-vapour got into the air pockets reducing the U-value of the EPS.

Mellor

I could well imagine that happening to sub standard EPS (water getting through where not 100% bonded). As for bitumen and EPS in conjunction, I have never been fond of using the two together, heat and EPS don't go well together. Its is more of an issue in warm roofs as at least an inverted can be let to cool (although it may not always happen, as in the case above). When I have been in a situation where I was detailing with EPS or similar and a hot applied finishing layer I insisted on a sheet of WBP ply inbetween to act as a heat sink.

ircoha

Some serious knowledge being imparted in this thread since I was here last:)


For completness am posting here a link to http://www.boards.ie/vbulletin/showthread.php?t=2055166109
as it will benefit others since it contains some of the same material

sydthebeat

Ben, come back to us when you have your BBA cert...

sinnerboy

As syd says - BBA cert please . On the face of it - good innovation

Do you have plans to develop stone wall cladding anchors and brackets ?

muffler

Listen guys. Please dont encourage people who are advertising their wares here.

If they feel the need to advertise then they can bloody well pay for it the same as the legitimate advertisers here.

Green&Red

Folks, I'm looking for a solution to a problem, I'm drylining a house but can't dryline the kitchen because it cant afford to be replaced. How do i go about this problem of having one massive thermal bridge in the hottest room in the house?
I could see other problems in the bathroom, at the stairs if its at an external wall etc.
Any suggestions greatly appreciated.

sydthebeat

Green&Red wrote: »

Folks, I'm looking for a solution to a problem, I'm drylining a house but can't dryline the kitchen because it cant afford to be replaced. How do i go about this problem of having one massive thermal bridge in the hottest room in the house?
I could see other problems in the bathroom, at the stairs if its at an external wall etc.
Any suggestions greatly appreciated.

whats the wall construction??

why cant you deconstruct the kitchen, and reconstruct after drylining? they generally are modular units screw fixed to the wall, also the counter top should be completely removable

Green&Red

sydthebeat wrote: »

whats the wall construction??

why cant you deconstruct the kitchen, and reconstruct after drylining? they generally are modular units screw fixed to the wall, also the counter top should be completely removable

Solid wall, the counter could be removed but would require a fairly serious effort (& money) to reconstruct the kitchen, not viable at the mo

sydthebeat

Green&Red wrote: »

Solid wall, the counter could be removed but would require a fairly serious effort (& money) to reconstruct the kitchen, not viable at the mo

why???

are the units not modular and separate???

i could de-construct my kitchen at home in a couple of hours by myself.. .and im a desk jockey!!!!

the only real extra work is extending electrics and plumbing to suit...

Green&Red

No its an older kitchen
Even if i could i'd have the same problem of thermal bridging in the bathroom and at the stairs

sydthebeat

i suppose it shows that internal drylining is only suitable if completely gutting a building first....

external insulation allows for insulating while affecting the internal minimally...

the only thing i can suggest is consider each room as zones, and try to separate each room by use of good quality solid doors, and draught strip the hell out of them, in order to try to trap heat in each room, as opposed to allowing heat travel from 'warm' rooms to 'cold' rooms....

Green&Red

Ya but that leaves you with the problem of the kitchen being a warm zone and ur losing heat to external space. There must be some way of getting around it

sydthebeat

yes there is, externally insulate....

Green&Red

They dont want external insulation, i had looked at it but no deal

sydthebeat

you cant insulate externally,
you cant insulate internally,
you cant de-construct and reconstruct the kitchen, stairs, bathroom...

is this work being done in order to access a grant?

Green&Red

Its being done because there is a grant, they dont want the external insulation, they know dry lining and what it does and want it, no talking to them about anything else. I'm just giving them a hand, and i'm worried about the problem of there being external walls that are not insulated

sinnerboy

Don't over complicate things .
I drylined my kitchen / diner about 2 years ago - to the diner part only . So the kitchen is not insulated and won't be untill I can replace it . No biggie .

sydthebeat

Green&Red wrote: »

Its being done because there is a grant, they dont want the external insulation, they know dry lining and what it does and want it, no talking to them about anything else. I'm just giving them a hand, and i'm worried about the problem of there being external walls that are not insulated

Ok,

Firstly, I would simply explain to them that undertaking this work under the situation youve described is not economical. They cannot afford to do the job properly so they should not undertake the work at this stage.

Secondly, what they are trying to do WOULD NOT comply with the requirements for the grant anyway (assuming this is the home energy savings grant). In order to comply the first measure of internal insulation is "Measures used to achieve the internal insulation of walls can include composite insulated dry-lining boards or any other approved system where insulation achieves a full coverage of insulation across the wall."

your clients cannot achieve a full coverage if they are not willing to remove kitchen stairs etc..

Green&Red

That was what i was looking for a solution to, the full coverage, theres no real point in dry lining half the room, with or without the grant.

Unfortunately they're no my clients

At least not the paying variety!

sydthebeat

There is no other options at this time unfortunately.....

as SB says, dryline what you can, but its pointless drylining part of a wall.

sinnerboy

Depends on context I suppose . In my case the rear elevation , is approx 2/3 dining + 1/3 kitchen . The kitchen is behind an archway so there is a visual break between the two spaces .

The dining area is a lot more comfortable than before dry lining - the inner surface of the the drylined walls don't absorb radiant heat from the noggin' as you watch tv any more .

And so far the only mushrooms in the kitchen are the ones I get from Tesco's . We do open the windows when cooking so condensation is not allowed to build up excessively.