External wall insulation - help!!!

zipee

Hi

I am hoping to get external wall insulation. I can't get the foam, I have cavity blocks as opposed to cavity wall. So I have had someone out to look over the house. Semi D built 1960ish and bloody freezing!!

What thickness should the polysterene Panels be???

He says they put aluminium on the bottom and a different polysterene (like what is in a swimming board and it's waterproof). Does this sound right?? I probably have left our huge bits in what he said but you hopefully get the idea.

Finally, my satelite dish. Can it be put back on over the polysterene or should I leave it and let them work around it????

Any ideas of a ball park figure for a small 3 bed semi d in Dublin for this type of insulation??? Just a vague idea.

Any idea how much I would save on heating by doing this?

Any other pointers?

Many thanks

sinnerboy

ball park cost €110 m2 wall area

below dpc line extruded polystyrene is needed - expended can absorb ground moisture

install the max thickness possible . most of the cost is labour and equipment . so to go from 100mm to 200mm may cost a relatively modest cost uplift circa € 10 m2

downpipes , alarm boxes , sat dishes should be removed and refit onto hardwood or dense pvc spacers

projecting conc cills should be cut flush - otherwise huge cold bridge

if you afford it - say €200 - 250 per window remove and reinstall them flush to the outer block face so that the frame align to the insulation - to minimise heat losses at jambs head and cill . Then take the opportunity to install air tightness tapes internally

Last but not least - only use a certified system - search here
http://www.nsai.ie/Our-Services/Certification/Agrement-Certification/Search-Agrements-Certificates.aspx

And - yes it will be worth it big time

.

zipee

Many thanks sinnerboy! All makes sense. If I could pick your brains once more? PVC sills?? Remove/replace/leave as is???

I think he mentioned extending them??

Finally I have a conservatory. He says his scaffolder can work round it and they can do the wall above it. Should it be the extruded polysterene for a few inches above this roof to prevent moisture getting in??? Then the normal stuff rest of the way up?

Many thanks again:)

sinnerboy

You have pvc cills now ? If so replacements will be needed to extend to cover the insulation

No Need for extruded ps above ground

zipee

sinnerboy wrote: »

No Need for extruded ps above ground

So the moisture from a wet roof that is kind of tongue and grooved effect (ie conservatory) wont get in???? Terrifeid of causing damp!:o

Thanks!

zipee

Absolutely last questions!

I am defo getting external insulation. But I want to get the best thickness that I can. 2 guys out to price now and prices are similar. But both quoting for 100mm boards. Now I asked the 2nd guy why only 100mm and not 200 or 300mm and he said "ah yes you can do that but why? Anyway you are governed by your fascia/soffit. Might be able to stretch you to 150mm"

Is this true? Can I extend them? Do they still have to overhang the wall and by how much? I have no other insulation at all! Cavity block walls which has been plastered directly over! Freezing! Just would pay the extra if I thought it would make a difference.

Finally! If you have 100mm insulation on outside, is this the same as 100mm on the inside in internal foam boards??? Still weighing up the best option.

Many thanks!

sas

Hey Zipee,

What type of insulation are they talking about?

There are 4 types typically available:
1. Phenolic
2. Mineral\Rock Wool
3. Grey EPS
4. White EPS.

They are probably talking about 1. I would have big reservations about this as it had its certification withdrawn on an IAB cert recently because of issues with water affecting it.

Option 3 would be the next best insulator.

Good luck.

trevdahead

sas wrote: »

Hey Zipee,

What type of insulation are they talking about?

There are 4 types typically available:
1. Phenolic
2. Mineral\Rock Wool
3. Grey EPS
4. White EPS.

They are probably talking about 1. I would have big reservations about this as it had its certification withdrawn on an IAB cert recently because of issues with water affecting it.

Option 3 would be the next best insulator.

Good luck.

thats the iab playing silly buggers,the board will be certified in about a month or 2,according to the iab.all down to money id say

zipee

OK I know I am clueless but I think it was white polysterene?? :rolleyes: So is that white eps???? He did show me another and said he has used it in the past but isn't now as it isn't approved and he feels there were probelms with it. Didn't say what problems but that it wasn't covered at the moment.

sas

trevdahead wrote: »

thats the iab playing silly buggers,the board will be certified in about a month or 2,according to the iab.all down to money id say

I rationalise it this way. EWI systems to the best of my knowledge originated in Germany and the surrounds. I haven't come across 1 German system that uses Phenolic. They are at it alot longer than us. Just because the lion needs to inject its product into a market doesn't mean it's suitable.

All of the other 3 are used.

The IAB didn't withdraw the certification lightly I'd imagine.

I don't see how it could have been down to money. The cert had already been issued 2 years previously with Phenolic as an option. It was subsequently withdrawn.

Time will tell however.

sas

zipee wrote: »

OK I know I am clueless but I think it was white polysterene?? :rolleyes: So is that white eps???? He did show me another and said he has used it in the past but isn't now as it isn't approved and he feels there were probelms with it. Didn't say what problems but that it wasn't covered at the moment.

Yeah, EPS is expanded polystyrene. I would take what you've said as a very good sign personally.

zipee

zipee wrote: »

Absolutely last questions!

I am defo getting external insulation. But I want to get the best thickness that I can. 2 guys out to price now and prices are similar. But both quoting for 100mm boards. Now I asked the 2nd guy why only 100mm and not 200 or 300mm and he said "ah yes you can do that but why? Anyway you are governed by your fascia/soffit. Might be able to stretch you to 150mm"

Is this true? Can I extend them? Do they still have to overhang the wall and by how much? I have no other insulation at all! Cavity block walls which has been plastered directly over! Freezing! Just would pay the extra if I thought it would make a difference.

Finally! If you have 100mm insulation on outside, is this the same as 100mm on the inside in internal foam boards??? Still weighing up the best option.

Many thanks!

Thanks sas but any ideas on my question above????

Many thanks again!

sinnerboy

I would aim to keep at least a 75mm-100mm overhang to maintain decent weathering ( keep the building dry ) .

100 external is superior to 100 internal because it extends continuously over the wall face - internal walls and your first floor won't allow internal boards to do that

Even if you "only" get 150mm on - you won't know yourself . You will feel the difference in comfort and in fuel bills

zipee

sinnerboy wrote: »

I would aim to keep at least a 75mm-100mm overhang to maintain decent weathering ( keep the building dry ) .

100 external is superior to 100 internal because it extends continuously over the wall face - internal walls and your first floor won't allow internal boards to do that

Even if you "only" get 150mm on - you won't know yourself . You will feel the difference in comfort and in fuel bills

:D:D Thanks sinnerboy! Made my day! Decision now made! Here's hoping for a warm house by end of Jan 2010!

luckat

How much does that per-squared-metre price work out to on one wall of an average 3-bed semi?

I was thinking of looking at this, but my place is a typical 1930s pebble-dash semi. Not sure about the dash... not sure about the price.

There's a grant of €4k towards external insulation, but if the cost is €20k, say, it wouldn't be easy for most people to find it rattling around in a back pocket. And it's always important to look at the cost against the savings in heating.

Poor Uncle Tom

luckat wrote: »

How much does that per-squared-metre price work out to on one wall of an average 3-bed semi?

I was thinking of looking at this, but my place is a typical 1930s pebble-dash semi. Not sure about the dash... not sure about the price.

There's a grant of €4k towards external insulation, but if the cost is €20k, say, it wouldn't be easy for most people to find it rattling around in a back pocket. And it's always important to look at the cost against the savings in heating.

Please see post No. 2 of this thread.
If you have a specific question regarding costs it should be asked on a seperate thread on the prices/costs sub-forum.

Builderfromhell

I've installed External insulation in a few places and would concur with everything Sinnerboy has said.

If you have a concrete tiled roof you may consider adding lenght to the rafetrs and simply adding one more tile. Typically this involves taking dis-coloured tiles from one side of house and putting theses where tiles can be seen. New tiles go where not seen easily. You can then increase thickness to 200mm EPS. That's what i would do.
Fitting satelite dishes, external taps etc. are no problem for experienced installers.

luckat

Poor Uncle Tom wrote: »

Please see post No. 2 of this thread.
If you have a specific question regarding costs it should be asked on a seperate thread on the prices/costs sub-forum.

Saw post No 2 of this thread. Didn't understand it.

muffler

sinnerboy wrote: »

ball park cost €110 m2 wall area

Poor Uncle Tom wrote: »

Please see post No. 2 of this thread.

luckat wrote: »

Saw post No 2 of this thread. Didn't understand it.

Condensed for you

luckat

muffler wrote: »

Condensed for you

Thanks. Didn't help. €110 m2? What? Is this some code?

Poor Uncle Tom

Do you really not understand "One Hundred and Ten euros per square metre of wall area"?

muffler

luckat wrote: »

Thanks. Didn't help. €110 m2? What? Is this some code?

In fairness unless you are into building works/design/selling etc then it may not have been awfully clear but my Poor Uncle Tom has explained it above.

luckat

Ah, I see now. How do I measure wall area on a vertical wall?

Poor Uncle Tom

Length x Height = Area

(every wall is vertical)

luckat

Sorry, I was unclear. How do I measure the height of a wall? Go up a ladder and drop a tape measure down? Or is there an easier way?

Come to think of it, this would be useless anyway, as I wouldn't be able to convert the measurement into square metres.

Since no one can give me a rough per-wall price guideline on insulating a typical three-bed semi, I'll say thank you and leave this discussion.

muffler

luckat wrote: »

Since no one can give me a rough per-wall price guideline on insulating a typical three-bed semi, I'll say thank you and leave this discussion.

We're going round in circles here. If you cant help yourself then you surely dont expect others to help especially when they dont know what size the walls are.

luckat

Honestly, I wouldn't see it as a hugely difficult question to ask an experienced person - three-bed semis don't vary that much.

muffler

But you asked for a figure for 1 wall and we dont know the size of that wall. I dont want you going away from this forum in the belief that either (a) it is well within your budget or (b) that you cant afford it and it then turns out that either scenario could be wrong.

Ring a local insulating company so and get a quote from them and just to note that grants are only paid out bt the SEI where all walls are insulated - not just one.

luckat

Ah, that solves it, in that case. This is one of those 1930s redbrick-to-the-hips houses with pebble dash around the back and side, but rebrick clothing the front first floor. It wouldn't be possible to insulate it all around without materially changing the look of the house. No problem.

Idbatterim

Op can I ask why you are going with external insulation?

S Connor

External Insulation!! Be afraid be very afraid. I have just got it done and my house is a compleate mess. Do very careful research of your builder. Cost 10,300 euro for a 3 bed semi. Am now fighting for a refund to pay for a redo. I have been told when done properly its fantastic.