External Wall insulation. Yes or No ?

Leiva · 09-12-2012 11:22am #1

Hi,

I am buying an extended 3 bed semi built mid 1970's and the first thing I will be doing is upgrading the central heating system to GFSH, but I am also thinking I will be wasting my time if I dont get the house properly insulated.

I am reluctant in doing internal insulation due to losing some room space etc so the external route seems the best option.

I see a builder in the area has been getting some business, as a number of homes in recent weeks have got EWI, so I might knock in and ask one of these completed house if they would recommend, and if they feel the difference from their new insulation.

Has anyone on here retro fitted EWI to their home and what do you think of it.

Ta in advance.

edanto · 09-12-2012 12:47pm

I've been looking into this question for a while and have settled on External over Internal (in my case).

One interesting document was this paper which compared simulations of various types of internal insulation and found a high condensation risk.

http://www.josephlittlearchitects.com/documents/Breaking_the_Mould_5_Construct_Ireland_Issue_12_Vol_4.pdf

Fair enough - it's only a simulation - but we haven't had the passage of enough time to know if internal insulation will result in widespread sick building, and that paper was enough to put me off internal insulation.

Having said that, there are plenty of experts here that will be able to give you advice, I'm only an amateur.

My two cents would be to hold off on the external insulation until you've decided what other improvements you may do to the house - would you plan any extensions? No point in paying to externally insulate a wall that will shortly be knocked out.

Does the roof overhang enough for external (most do)?

For this winter, you may get by with just lots of extra attic insulation, and then take a few months to plan things, and if needs be, then do external insulation in summer/autumn.

spatchco · 09-12-2012 12:56pm

well for whats its worth i had my house insulated externaly about 3-4 years ago and have not looked back,best money i ever spent it a 3 bed semi and we got the loan am also saveing a fortune on oil heating.

stimpson · 09-12-2012 12:59pm

Get lots of quotes. We had it done this time last year and there was €1500 between the quotes. The cheapest quote was for 120mm as opposed to 100mm. We got vents put in every room. As the weather got colder this year I noticed some condensation in one of the bedrooms, but opening the vent to half way seems to have helped.

Performance wise it's amazing. I'd say our heating oil bills have been cut in half. more importantly, the house is much warmer. Normally we would get up at this time of year and it would be freezing. This morning the stat said 18 deg and the boiler hadn't been on since 11 last night.

The guy I used was from Ashbourne. I can PM you his details if you're nearby.

Leiva · 09-12-2012 1:09pm

stimpson wrote: »

Get lots of quotes. We had it done this time last year and there was €1500 between the quotes. The cheapest quote was for 120mm as opposed to 100mm. We got vents put in every room. As the weather got colder this year I noticed some condensation in one of the bedrooms, but opening the vent to half way seems to have helped.

Performance wise it's amazing. I'd say our heating oil bills have been cut in half. more importantly, the house is much warmer. Normally we would get up at this time of year and it would be freezing. This morning the stat said 18 deg and the boiler hadn't been on since 11 last night.

The guy I used was from Ashbourne. I can PM you his details if you're nearby.

Thanks all for the replies.

Yes please PM the details .

edanto · 09-12-2012 1:19pm

Levia, I'll be looking to do this in the next year or two, would you mind PMing any recommendations you get to me also, please?

MicktheMan · 09-12-2012 1:59pm

As has been said here, ewi can deliver a huge improvement to the insulation of a house. However, it will be of little value if the house is draughty and I have seen several cases where a significant sum has been invested in ewi without getting any of the expected benefits because the main heat loss mechanism in the house was not heat conduction through the walls but instead the lack of airtightness.
My advice to anyone thinking of ewi is to have a full heat loss survey including an airtightness test (note, this is not a BER) by an experienced firm and to ensure that the ewi company quote for going up past the soffit to meet the roof insulation and also down to the footings (a lot of the less reputable co's don't do this, so beware).

germack3 · 10-12-2012 6:29pm

As long as the extermal wall is solid if not the heat is escaping into the cavity and rising into the attic space even if you get a thermal scan on the outside of the house it will show no heat loss again because the heat is rising into the attic, if its a solid wall ok. do get quotes and friend of mine recently got their house insulated abnd they got 4 quotes and there was just over €1000 from the cheapest to the most expensive.

dvpower · 12-12-2012 9:55pm

Does it ever make sense to externally insulate a single wall?

I have a semi-d with a large concrete rendered side wall, but a mix of red brick and pebble dashing on the front. I figure that it would be a good deal cheaper just to do the side wall (which is also the coldest side of the house), but would it
a) be a good deal cheaper? and
b) provide any real benefits?

stimpson · 12-12-2012 10:10pm

You won't get the grant for that. To be eligible you need to insulate all external walls. I doubt it would be particularly effective either as I would assume the heat will just escape through the other walls. I'm sure someone with more knowledge will be along to weigh in.

Leiva · 13-12-2012 4:26pm

Some people are suggesting I should just insulate internally with "warm board" .. whats that, any good ?

isup · 10-01-2013 9:46am

germack3 wrote: »

As long as the extermal wall is solid if not the heat is escaping into the cavity and rising into the attic space even if you get a thermal scan on the outside of the house it will show no heat loss again because the heat is rising into the attic, if its a solid wall ok. do get quotes and friend of mine recently got their house insulated abnd they got 4 quotes and there was just over €1000 from the cheapest to the most expensive.

Im looking into this at the moment. My house is cavity blocks. Do wlyou think id be wasting my time and money externally insulating this way?

sbsquarepants · 10-01-2013 10:02am

Leiva wrote: »

Some people are suggesting I should just insulate internally with "warm board" .. whats that, any good ?

It's basically plasterboard with insulation bonded to one side. AFAK it is quite effective and reasonably inexpensive, you do loose a small bit of floor space internally, which even though quite small (region of 150mm) is noticeable in small rooms, you're basically loosing close to a foot on the width and the length of each room.
If your house is constructed with a cavity between the inner and outer walls, as most houses less than 30 or 40 years old are, you could also look at having it filled with polystyrene beads - my parents house was done this way a couple of years back, coupled with doubling the attic insulation and i have to say it has made a big difference.

Ush1 · 10-01-2013 10:44am

stimpson wrote: »

You won't get the grant for that. To be eligible you need to insulate all external walls. I doubt it would be particularly effective either as I would assume the heat will just escape through the other walls. I'm sure someone with more knowledge will be along to weigh in.

I thought you got the grant if "most" walls were externally insulated.

Any ideas on pricing of an air tightness test and thermal camera survey?

Ush1 · 10-01-2013 10:45am

germack3 wrote: »

As long as the extermal wall is solid if not the heat is escaping into the cavity and rising into the attic space even if you get a thermal scan on the outside of the house it will show no heat loss again because the heat is rising into the attic, if its a solid wall ok. do get quotes and friend of mine recently got their house insulated abnd they got 4 quotes and there was just over €1000 from the cheapest to the most expensive.

If the attic is well insulated though surely most of the heat will be kept in the house?

pinksalt · 03-07-2013 3:58pm

Mick that is very useful comment. would you be able to recommend someone to look at the air tightedness and advise on getting the quotes for EWI. thanks a million Mick.

MicktheMan · 03-07-2013 4:51pm

PM sent

Mr.Magoo2 · 03-09-2013 6:47pm

Can people share their experience with the following external wall insullation systems

1. Bostik (ClimaTech)
2. Baumit System
3. Weber (therm XM or XP)

Also, can somebody advise as to which is the better of the 3 systems based on a system of 100mm2 EWI system. Better in this context can refer to heat retention capacity (w/mK), and/or reliability. (apparently some websites I have checked indicate that these are all the same at 0.27w/mK (but I have been unable to validate these sources).

Advise would be greatly appreciated.

thanks in advance

jussayeh · 28-07-2014 12:09pm

Mr.Magoo2 wrote: »

Can people share their experience with the following external wall insullation systems

1. Bostik (ClimaTech)
2. Baumit System
3. Weber (therm XM or XP)

Also, can somebody advise as to which is the better of the 3 systems based on a system of 100mm2 EWI system. Better in this context can refer to heat retention capacity (w/mK), and/or reliability. (apparently some websites I have checked indicate that these are all the same at 0.27w/mK (but I have been unable to validate these sources).

Advise would be greatly appreciated.

thanks in advance

I think you check on the SEAI site for products that they certify and approve for ewi. My mother had her house done last July. She got a number of quotes the cheapest being 17k, 30k, right up to 37k ... imagine for the same job ... Needless to say she didn't bother with the cheapest quote but took references from the other two who had done a lot of houses around the Dublin area. She decided to go with the dearest quote actually because he was the only one who was happy to take the soffits down and runn the insulation right up under the attic eaves.
They also finished off the window boards better than any of the houses we knocked on to look at during our research. The window boards weren't hollow either - some of them are and are apparently very noisy if its raining heavily - like rain on a corrugated roof.
Nothing was too much trouble for them and they were an absolute pleasure to deal with.

The house was originally a 1940's white pebble dash finish but my mother changed the look of it completely by chosing a really nice off-white smooth render which only needs painting every 10 years or so - no more pebble dash!!
The product they use is SEAI certified and has been used for over 30 years apparently so it's a proven system. Only draw back is you have to open the windows in the summer to let the heat in as the insulation keeps the heat from the sun out. A small price to pay for a comfy and cosy home for the other 9 months of the year when its freezing! Anybody who wants to see the house or any further info just pm me.

stimpson · 28-07-2014 2:00pm

jussayeh wrote: »

My mother had her house done last July. She got a number of quotes the cheapest being 17k, 30k, right up to 37k ... imagine for the same job ... Needless to say she didn't bother with the cheapest quote but took references from the other two who had done a lot of houses around the Dublin area. She decided to go with the dearest quote actually because he was the only one who was happy to take the soffits down and runn the insulation right up under the attic eaves.

37K is hardly a small price to pay. How long until it pays for itself? That would have paid my oil bill for nearly 20 years pre-insulation.

Mine cost less than 5K after the grant. We spent 1200 on a composite front door and changed the boiler for a condensing natural gas one for ~2K. Our annual bill for oil was about 1800pa and has now dropped to ~800, so payback is about 8 years.

jussayeh · 29-07-2014 4:20pm

I made a mistake on the price sorry .... she paid 27k not 37k ... and she got the full grant of 3.4k or something ... she got it done last July and has only had one winter to gauge savings but I'll check with her and post back later

.. and will post pics of the soffits and sills as requested by pm when I'm back up in Dublin next week.

jussayeh · 31-07-2014 2:24pm

stimpson wrote: »

37K is hardly a small price to pay. How long until it pays for itself? That would have paid my oil bill for nearly 20 years pre-insulation.

Mine cost less than 5K after the grant. We spent 1200 on a composite front door and changed the boiler for a condensing natural gas one for ~2K. Our annual bill for oil was about 1800pa and has now dropped to ~800, so payback is about 8 years.

In July 2013 the cost per sq metre for ewi varied between 100 and 150 euro according to all the research I did. Mum paid about €100 per sq metre and she had an area of about 320 sq metres to do, with the 3.6k grant the total cost was 27.5k.

She tells me, although I haven't had a chance to make sure these figures are 100% correct but on her own estimation she says she used to spend 2.8k pa on gas and this year she spent 2k.

Drift · 31-07-2014 2:42pm

That works out at a payback period of 35 years!

stimpson · 31-07-2014 2:49pm

jussayeh wrote: »

In July 2013 the cost per sq metre for ewi varied between 100 and 150 euro according to all the research I did. Mum paid about €100 per sq metre and she had an area of about 320 sq metres to do, with the 3.6k grant the total cost was 27.5k.

She tells me, although I haven't had a chance to make sure these figures are 100% correct but on her own estimation she says she used to spend 2.8k pa on gas and this year she spent 2k.

So that a 35 year payback. Is it a bungalow?

I only had about half that area, but I just looked at the quote and it was around €60 per square meter before the grant is taken into account.

MicktheMan · 31-07-2014 3:13pm

jussayeh wrote: »

on her own estimation she says she used to spend 2.8k pa on gas and this year she spent 2k.

Couple comments on this:
1. It's not all about insulation ... see post #7 above
2. Some economic savings get absorbed by improved comfort levels (i.e. house heated to a higher degree post insulation install)

sydthebeat · 31-07-2014 4:41pm

Drift wrote: »

That works out at a payback period of 35 years!

assuming no price increases....

energy prices are rising at approx 7% per annum.
making that payback period 18 years

notwitstanding the comfort and health benefits

stimpson · 31-07-2014 5:20pm

sydthebeat wrote: »

assuming no price increases....

energy prices are rising at approx 7% per annum.
making that payback period 18 years

notwitstanding the comfort and health benefits

...but you have to subtract the general rate of inflation from the 7% if you're doing it properly, bringing you back to around 24 years

sydthebeat · 31-07-2014 6:03pm

stimpson wrote: »

...but you have to subtract the general rate of inflation from the 7% if you're doing it properly, bringing you back to around 24 years

arguable.

whos to say the €27,500 wouldnt have been spend on something else in this year....

the nearest argument you can make is to argue what the €800 would have achieved in a long term deposit account... but again that assumes the €800 wouldnt have been spend elsewhere.

also doesn't include real value addition to house value etc

there are many ways to argue payback periods, and very few would subtract general inflation from energy cost inflation.

stimpson · 31-07-2014 6:25pm

sydthebeat wrote: »

arguable.

whos to say the €27,500 wouldnt have been spend on something else in this year....

the nearest argument you can make is to argue what the €800 would have achieved in a long term deposit account... but again that assumes the €800 wouldnt have been spend elsewhere.

also doesn't include real value addition to house value etc

there are many ways to argue payback periods, and very few would subtract general inflation from energy cost inflation.

Of course you have to take it into account. You could spend it on a car, but thats besides the point - you'll still need to come up with the 27K (in real terms) in the meantime to pay your bills.

While the amount of cash will increase over time due to energy price inflation, wages increases and/or interest will make up some of the difference.

Point taken about comfort and added value to the house, but I still think the playback time is huge.

External Wall insulation. Yes or No ?

Comments