Insulation

BoozyBabe · 11-03-2008 10:21am #1

Hi All,

I've a feeling I'm going to be wrecking your heads for atleast the next 12 months, so sorry in advance!!!

This site is great, I sat up reading threads until my eyes couldn't stay open any longer. there's such a wealth of information here, but most importantly, unbiased information!

I'm building a 2500sq ft block house & I'm now considering the heating system to install in it & whether to put HRV into it, etc, but readless of all the fancy technologies, I know none of them will work to their full potential if the house isn't well insulated.

So, this is why I'm here.

No offence to any builder here, but where I am, I'd imagine a lot of them are old school & sure "this is how I've been building them for years & this is who it's done & it's more than adequate" would be the response when two young people ask them to change the spec of something.

Basically I believe we should insulate the house to the high heavens, but I don't know what that is if I don't know what the normal standard is. & I'm afraid of getting fobbed off by the builder.

So, I need your help / advice:-
Can you tell me the insulation normally installed on the floor & what I should bump this up to if not going with UFH. & also, what I should raise it to if going with UFH. Also, if there thinner stuff that will do as good a job as thicker stuff when doing UFH as I believe this raises the floor quite a bit.

Then, what about in external walls:- what's the norm & what should I aim for?

What's needed in internal walls?

If I put UFH on the 1st floor, what way should I insulate it? I've heard comments that it doesn't really matter, as you're not actually losing heat if it escapes back downstairs, but surely that's not the point, if I've UFH upstairs, then I want it to heat upstairs

How should I insulate the attic? I know I should insulate between the roof trusses (or whatever they're called), but with what, but on top of that, should I also insulate the floor space of the attic?

This may only apply to UFH, but I've heard people talking about insulating along the walls also as a lot of heat is lost here. What's this they're talking about?

What's the best way to insulate around windows & doors etc?

What else am I missing?

Sorry for all the questions. I'm clueless about this.
I haven't decided if I'll go the HRV route yet, but I want my house as airtight as possible anyway, & regardless of what heating system I ruun with, I want it to have to work as little as possible, so I want to get the insulation right, so all help is appreciated.

Also, I understand that chimneys are one of the biggest losers of heat in a house, yet I don't think I'm going to convince the Mr not to build two in the house. On another thread the question was asked about HRV & chmineys & the idea of trapdoors was mentioned to close off the chimney when not in use.
Are these sufficient in keeping the heat in the house. Can a HRV system work with these?

With the new BER cert, say I build my house & it only gets a D rating, yet I never intend on selling or renting, is it basically just telling me my house could be more economical, or can I be forced to improve its rating?

& Lastly (again sorry it's SO long!!!) Whats the New Part L of the Buildings Req thingy all about. (I've no idea what the name of it is).
It comes into affect on the 1st of July this year. If I've my PP lodged on or before 30th June this year & most of the building work done before 1st July 09 I'm exempt, which hopefully I will be, but exempt from what exactly?
Am I right in saying that after that, all new builds must incorporate some type of renewable energy source.
Is this as basic installing all CFL light bulbs in the house, or is it more than that such as installing at least 1 solar panel to comply with the regulations?

davidoco · 11-03-2008 10:58am

First of all give up the drink, as you don't want to be turning up on site with a hangover and find that the blocklayer missed a window

You might find the money spent on a consultation with a BER assessor now as money well spent. They will attempt to give your house a rating based on the standard cavity/floor/ceiling insulation and then make suggestions about how you can improve upon that.

Remember there are now probably at least 10 different (and acceptable) techniques to insulate your walls and roof and each has it's own merits.

A lot of insulation issues come down to cost, measure every ground floor and roof external area and exterior wall area and get a final sq m figure. For example a 1400 sq foot bungalow would have about 400 sq m (give or take 10%) of area requiring insulation. So that’s 400 x ? per metre cost of insulation. Basic 300 mm fibre glass costs at least €10 per metre, 300 mm semi rigid batts up to €30.

scalerb · 15-03-2008 7:57pm

My understanding and expecting to be corrected

A concrete floor with no insulation - Divide the perimeter by the area of your floor

Perimeter / Area Ratio u value

0.1

0.22
0.2

0.37
0.3

0.49
0.4

0.60
0.5

0.70
0.6

0.78
0.7

0.86
0.8

0.93
0.9

0.99
1.0

1.05

A floor needs a u value of 0.25W/m2K, to figure out how much insulation you need to add to your floor divide 1 by the u value and this gives you a r value.

ie. p/a raito of 0.8 gives me a u value of 0.93 or a r value of 1.07
u value needed is 0.25 or a r value of 4

so 4 - 0.93 = 3.07
Now you need to search insulation suppliers web sites to get a k value(Lambda)

ie kingspan 0.021 , Aerobord 0.031

Now you muiltply the r value needed (3.07) by the k value
ie. 3.07 x 0.031 =.095m This gives you the thickness of insulation in meters required to meet regulations
As standard 100mm is put in to most houses.

Now i think i need to sit down ,Ted

sinnerboy · 16-03-2008 3:53pm

look to pages 3 and 4 here for an overview strategy

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,15662,en.pdf

NB - UFH in floors - MIN u value 0.15

use HRV

appoint an air tightness tester do do pre test inspection first ( after roof + windows , but before plastering ) and then test after plastering

don't use open fire , or if you must fit a baffle to it , to be closed when fire is not in use

scalerb · 16-03-2008 6:22pm

A typical concrete block cavity wall with 100mm block 100mm cavity 100mm block plastered both sides would have a u vale of approx 0.92w/m2K (r 1.08)

Regulations require 0.27w/m2K (r 3.70)
so 3.7-1.08 = 2.62 x .021 ( k value ) = .055m
as standard 60mm in cavity and 40mm air cavity is constructed.

As a target passive houses are typically constructed to have a average u value of between .10w/m2K to .15w/m2K (lower u value better)

concrete floor with p/a ratio of .8 would need 280mm of ESP (aerobord) or 190mm of pir (kingspan) to reach .10w/m2K

Walls would need 276mm of eps or 190mm of pir , to do this you could put 60mm pir in cavity and dryline with 130mm pir or have a wider cavity or consider a different form of construction such a concrete form or external insulation.

Internal walls should be left un-insulated to act as a thermal mass to soak up the heat available during heating hours and release it when the house is cooling down.

ufh up stairs no idea

Mellor · 16-03-2008 9:32pm

scalerb wrote: »

Internal walls should be left un-insulated to act as a thermal mass to soak up the heat available during heating hours and release it when the house is cooling down.

they should also be left uninsulated because it will have no effect what so ever (except in zoned cases)

Femelade · 20-03-2008 1:14am

Sorry to be posting about this again , i can see there is already a good few threads on insulation, i know nothing about building atall, but i told my boyfriend i'd ask ye guys a question for him, Basically, The block work will be starting on his house in about 2 weeks and he needs to tell his builder what kind of insulation he needs.
The builder swears by this stuff that you just pump into the wall cavity, as it gets to every nook and cranny..But my boyfriend reckons he might just be saying that as it will lighten his own workload, A few friends of his tell him that Kingspan is the way to go..but to be honest these people he has asked are also in the process of building , but not actually living in their house yet, so they cant really tell which is better can they?

So, thats it really, which insulation is best..the pump one or kingspan..?

apologies for my lack of knowledge on the right terms to use here.

muffler · 20-03-2008 10:42am

I can understand your reason behind this poll but really and truly its not as clear cut as you may think. It would be impossible to vote one way or the other because of building regulation requirements and the properties of the various insulation types.

I doubt if it will get much traffic but keep an eye on this forum as Im going to start a thread later about insulation.

smashey · 20-03-2008 10:57am

Poll closed as it's not really the way to go about things.

Also, Femmy I have merged your threads and wito keep them all in one space for ease of reference.

20-03-2008 2:24pm

Personally I dont like the pumped insulation as it negates the cavity in a cavity wall, it is easier for the blocklayer but if they are sloppy with keeping the cavity clear then there will be voids in the insulation and a possability of water ingress. also and more importantly, some pumped insulations dont provide a very good u-value.
Kingspan (or similar) is more expensive but generally provides a better u-value but can still cause problems if not done right.
Talk to a BER assessor if you can or an architect or technician to get the best advice on what type of insulation to use and where to get the most out of it. Like most things in building you'll find its easier to do now than retrofit.

ircoha · 20-03-2008 10:23pm

In my opinion getting the correct insulation-related workmanship is essential and when picking a particular product consideration should be given as to how easy it is to get right and what are the ways to reduce the risk of bad workmanship occurring.

For example,
perhaps a multi layer approach [2 by 50] as suggested by sinnerboy when dry-lining internally is a better option than a single layer [1 by 100] approach.
perhaps the fibre types are more forgiving than the rigid types.

Builders generally understand that a shoddy roof will leak so it gets done correctly more often than not as the evidence is pretty obvious.

However builders generally do not appreciate the importance of fitting insulation correctly, particularly since the workmanship is hidden and there is no obvious impact.

The main thrust of my concerns here is that you can have all the assessors and technicians and architects and engineers telling you what SHOULD happen,
As to MAKING it happen: well sin sceil eile

BoozyBabe · 20-03-2008 10:29pm

smashey wrote: »

Poll closed as it's not really the way to go about things.

Also, Femmy I have merged your threads and wito keep them all in one space for ease of reference.

Ye had me scratching me head there!!!!

I was going "I don't remem putting in a Pole

Thought I was going mad!!!:eek:, but I see a thread was merged.
At least I'm not going crazy, I don't think!!!

muffler · 20-03-2008 11:08pm

BoozyBabe wrote: »

Ye had me scratching me head there!!!!
I was going "I don't remem putting in a Pole

Thought I was going mad!!!:eek:, but I see a thread was merged.
At least I'm not going crazy, I don't think!!!

Its OK. Its just the full moon. You'll be fine in a couple of days

ircoha · 21-03-2008 12:32am

muffler wrote: »

I can understand your reason behind this poll but really and truly its not as clear cut as you may think. It would be impossible to vote one way or the other because of building regulation requirements and the properties of the various insulation types.

I doubt if it will get much traffic but keep an eye on this forum as Im going to start a thread later about insulation.

As a start for the insulation thread can I recommend the article on Insulation for Sustanability
from http://www.xco2.com/resources.htm

Insulation

Kingspan or Pump Insulation 1 vote

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