What type of external insulation works best below paved areas

Carlow52

My neighbour has just had the entire outside of his house dug out for paving.

The ground is c 300mm below where the paving will end so he is considering putting some external insulation in now so as when he insulates externally, the bit below the paving is done.

Is this worth doing? and if so what type should he look at/
All suggestions welcome.
Thanks

sinnerboy

Extruded polystyrene . Expanded can absorb water - risky below dpc

conor2949

When you say Extruded Polystyrene - do you mean Phenolic?

AMIIAM

All external insulation is crap. Just another pie in the sky idea.

sydthebeat

conor2949 wrote: »

When you say Extruded Polystyrene - do you mean Phenolic?

phenolic foam and extruded polystyrene are completely different materials....

1. Expanded polystryene (EPS). EPS is most common and least expensive. It's insulating value is about R-4 per inch (RSI=0.70 per 25 mm); it provides similar insulating value with dense fiberglass and mineral wool, depending on the density. It can be manufactured in three densities; the more dense the product, the better the insulating value and the more it costs. It should not be exposed to very high temperatures (167 degrees F; 75 degrees C) for long periods of time. It's insulating value is stable. It's permeability to water is relatively low, but it does not qualify as a vapor retarder. The product is normally white in color and is derived from petroleum products. EPS is used in the manufacture of most SIPs today.

2. Extruded polystyrene (XPS). XPS has 25% more insulating value for the same thickness as the foam used most frequently in SIPS today. Like EPS, XPS foam provides stable insulating value and has about the same sensitivity to high temperatures as EPS. Most XPS products are colored by manufacturers--blue, pink, yellow, green. XPS has lower permeability to water vapor; the thickness in a structural insulated panel would qualify it as a vapor retarder. XPS is more expensive than EPS.

also see here:
http://www.diversifoam.com/xeps.htm

sydthebeat

AMIIAM wrote: »

All external insulation is crap. Just another pie in the sky idea.

perhaps you can explain how your opinions are informed???

as your post can be considered contentious, if you cannot back up what you say, you will be subject to moderating action....

no biggy if youve a serious point to make....

AMIIAM

Exactly as I stated. External insulation is crap. Sold as internal spacesaving, sounds great idea. BUT it is new, not stood the test of time. Also it is soft textured, ie,. easily damaged. Supposedly protected by render! 5mm thick.What a bloody joke! Do architects have on the outside of their houses, NO. They bought proper cavity wall constructed houses. Need I say any more?

sinnerboy

http://www.ibp.fhg.de/literatur/fachz/Roz2.pdf

AMIIAM

The German climate is much drier than the Irish climate. Also it is new in Ireland. I would always let others buy and try rather than me. Methods of fixing to exterior walls are shoddy to say the least.

sinnerboy

AMIIAM wrote: »

The German climate is much drier than the Irish climate. Also it is new in Ireland. I would always let others buy and try rather than me. Methods of fixing to exterior walls are shoddy to say the least.

True. True . Your prerogative . Can you expand on this please - what fixing methods would satisfy you ?

sinnerboy

AMIIAM wrote: »

Do architects have on the outside of their houses, NO.

Yes - This one does

http://constructireland.ie/Vol-4-Issue-5/Articles/Passive-Housing/19th-century-ruin-renovated-with-passive-house-aims.html

AMIIAM wrote: »

Need I say any more?

A fair bit

sydthebeat

AMIIAM wrote: »

The German climate is much drier than the Irish climate. Also it is new in Ireland. I would always let others buy and try rather than me. Methods of fixing to exterior walls are shoddy to say the least.

as you have correctly stated, ireland has a 'wetter' climate than germany (we have higher humidity).....

therefore an insulation system designed to rid us of the sever problems we have in our own traditional construction would seem like a great, idea wouldnt it..??
EWI significantly reduces repeating and non repeating thermal bridges...
('cavity wall' and 'cavity block' construction is full of them...)
EWI undoubtedly results in the dew point being brought to the outside of the construction...
(commonly drylined 'cavity block' construction most certainly doesnt )
EWI insulation is inherently water proof...
(Badly constructed cavity wall construction allows moisture ingress all over the place.... sloped wall ties, incorrect or missing dpcs, incorrrect or missing dpc trays, services penetrations, mortar snots bridging cavity... etc etc)

Perhaps you'd like to put forward a coherent argument against it and we will debate it??..... after all, thats what these fora are for...

AMIIAM

Sure, It was economic madness allowing builders build shoddy houses, ie, Cavity block construction. This type of construction only belongs to farmyards. Cavity wall construction was and is the only time tested way of building dwelling houses. If properly built there are no thermal bridges. Alas, some are/were not properly built owing to blocklayers' incompetences. Builder' attitude is also unhelpful. (throw those blocks up so I can get roofing). With insulation properly installed within the cavity there is no need for EWI. I rest my case.

Carlow52

AMIIAM wrote: »

Sure, It was economic madness allowing builders build shoddy houses, ie, Cavity block construction. This type of construction only belongs to farmyards. Cavity wall construction was and is the only time tested way of building dwelling houses. If properly built there are no thermal bridges. Alas, some are/were not properly built owing to blocklayers' incompetences. Builder' attitude is also unhelpful. (throw those blocks up so I can get roofing). With insulation properly installed within the cavity there is no need for EWI. I rest my case.

The above encapsulates the problems with CWC: just look at the number of caveats/ifs and buts.

--

The measure of any true professional is to have an open mind on all possible solutions that are applicable to a project and then select the one that gives the best overall economic return within the client's constraints.

In the real world, which most of the posters here inhabit as opposed to the surreal fantasy world you seem to 'rest in', EWI has two main applications: retrofitting some of the existing housing stock and new build.

To dismiss EWI out of hand as you have done this far in this thread begs the question as to your true motives for contributing to this thread which, may I remind you, is about what type of insulation works best below ground in an EWI application for a retrofit.

Quite clearly a CWC solution is not a real option so if you have nothing useful to add to the question under discussion then don't bother.

sinnerboy

My ignore list grows....

AMIIAM

Carlow, Ignarance is BLISS.

muffler

Careful!