2 Year Old Extension that's cold - help needed

AlanD

Hi,

We have a typical 4 bed semi-d wood frame house in Limerick. 2 years ago we built on an extension and one of the things we wanted most, we didn't get. We wanted to ensure it was a warm extension. Instead it's losing heat faster than we can put in to it.

A brief description of the extension is that it is brick construction with 100mm insulation between outer and inner wall. It has a sloped 15 degree roof with just 7 inches between inside and outside. I think there is just fibre glass insulation in the ceiling. Unfortunately, we've got swivel recessed lights everywhere, so they are blowing a gale. But we've them sealed up and there's still no change.

We got a blower/thermal test done and it highlighted some areas for change, most of which we have taken care of. Most of the heatloss was not through the ceiling that we thought it might have been, but through the walls. Now the walls are packed with insulation and it was meticulously put in, so we're not sure how to solve the problem.

We've had some people look at it and all have just scratched their head not knowing how to solve our problem.

So I'm looking for someone who's job it is to look at a building and determine what needs to be fixed to make it more energy efficient and more importantly for us, warmer.

What sort of the person should I be looking for and could you recommend anyone? We want to fix it, but we want to be smart spending money so it's not wasted on useless mods.

Your help would be appreciated.

MicktheMan

AlanD wrote: »

Hi,

We have a typical 4 bed semi-d wood frame house in Limerick. 2 years ago we built on an extension and one of the things we wanted most, we didn't get. We wanted to ensure it was a warm extension. Instead it's losing heat faster than we can put in to it.

A brief description of the extension is that it is brick construction with 100mm insulation between outer and inner wall. It has a sloped 15 degree roof with just 7 inches between inside and outside. I think there is just fibre glass insulation in the ceiling. Unfortunately, we've got swivel recessed lights everywhere, so they are blowing a gale. But we've them sealed up and there's still no change.

We got a blower/thermal test done and it highlighted some areas for change, most of which we have taken care of. Most of the heatloss was not through the ceiling that we thought it might have been, but through the walls. Now the walls are packed with insulation and it was meticulously put in, so we're not sure how to solve the problem.

We've had some people look at it and all have just scratched their head not knowing how to solve our problem.

So I'm looking for someone who's job it is to look at a building and determine what needs to be fixed to make it more energy efficient and more importantly for us, warmer.

What sort of the person should I be looking for and could you recommend anyone? We want to fix it, but we want to be smart spending money so it's not wasted on useless mods.

Your help would be appreciated.

What size is the extension and how is it heated?

Does the extension heat up at all or does it lose its heat too quickly?

What was discovered with the "blower/thermal test"?

How airtight is the extension?

Has anybody done a heat loss calc including a ventilation / air infiltration losses?

How was it ascertained that the walls are the main problem and not the other elements?

More questions than answers I know but heat loss is rarely straight forward and experience plays a key role.

AlanD

MicktheMan wrote: »

What size is the extension and how is it heated?

It's just under 40sq.m has a dining room with an open (no door) double door space connecting it to the main house. This room has a 4m aluminium and glass sliding door. It's high quality double glazed glass and oddly enough this room is not the problem. There is an unheated small utility room then and at the back there is an ensuite bedroom. This room is about 5 degrees colder than the rest of the house and in the winter, it's freezing. The rad has a higher output than the size of the room.

MicktheMan wrote: »

Does the extension heat up at all or does it lose its heat too quickly?

The main room connected to the house does heat up. Not to a point where you could get it too warm. The bedroom, no. I'd have to put in an electric heater to make it warm, but give it 30 mins and it'd be cold again.

MicktheMan wrote: »

What was discovered with the "blower/thermal test"?

There were no major leaks in the extension. Just some small gaps around windows and sockets [all calked up now]. Plus the recessed lights which have been changed to a sealed unit. The mainhouse was the sieve!! But the mainhouse is warm, still though we'll sealing up the mainhouse too.

The thermal imaging found temp differences in the walls. Our extension is up against a boundary wall and so wasn't big enough to plaster the entire outside wall. This part was colder than the part plastered.

So maybe we need to plaster this wall.

MicktheMan wrote: »

How airtight is the extension?

It was pretty good apart from lights as above.

MicktheMan wrote: »

Has anybody done a heat loss calc including a ventilation / air infiltration losses?

blower test did some calcs....wasn't great, but major holes were in the main house.

MicktheMan wrote: »

How was it ascertained that the walls are the main problem and not the other elements?

temp differences could be seen on the inside of the walls which was odd. So the inside walls all have 100mm of insulation behind them right to the roof so the inside walls are cooling some how.

MicktheMan

So the ensuite bedroom is the problem, not the whole extension. How many external walls does this bedroom have and is it north or east facing?

what type of insulation is in the cavity? Is the unplastered external wall part of the bedroom?

I'm not sure what you mean by "thermal imaging found temp differences in the walls" ? Do you have any pics? Is there a distinctive temperature pattern?

AlanD

MicktheMan wrote: »

So the ensuite bedroom is the problem, not the whole extension. How many external walls does this bedroom have and is it north or east facing?

what type of insulation is in the cavity? Is the unplastered external wall part of the bedroom?

I'm not sure what you mean by "thermal imaging found temp differences in the walls" ? Do you have any pics? Is there a distinctive temperature pattern?

The ensuite bedroom would be the biggest problem. It has 3 external walls, 2 not fully plastered on the outer leaf. The extension is perpendicular to the back of the house which faces SSW.

I don't have pics of the thermal imaging but I was there when yer man was surveying the place. We could see the temp differences as clear as day.

I'm not convinced that the plastering is entirely the issue, if even it is an issue at all since behind the inside walls is insulation.

MicktheMan

AlanD wrote: »

The ensuite bedroom would be the biggest problem. It has 3 external walls, 2 not fully plastered on the outer leaf. The extension is perpendicular to the back of the house which faces SSW.

I don't have pics of the thermal imaging but I was there when yer man was surveying the place. We could see the temp differences as clear as day.

I'm not convinced that the plastering is entirely the issue, if even it is an issue at all since behind the inside walls is insulation.

Ah yes, but how dry is it?

AlanD

MicktheMan wrote: »

Ah yes, but how dry is it?

How dry is the insulation?

Good question. No idea.

So if i wanted someone to come out and assess the extension and take away all the guess work, what or who would i be looking for.

looksee

Three external walls is very exposed, even with insulation. We had a garage convertion like that that was so cold in winter it was totally unusable. We insulated the walls, but the biggest difference was insulating the ceiling and putting a pitched roof over the flat one that was there (though I think the insulation was what did it) and most important, we put rigid insulation into the floor - which was a slightly raised wooden floor over concrete.

We recently took up the (wooden) floor of a small conservatory extension (mostly glass) which opened into the house (no door) and put in rigid insulation and the difference is amazing. We have also put a small rad in that area. Previously the cold caused a convection effect which made it seem as though there was a draught, but that has gone.

AlanD

looksee wrote: »

Three external walls is very exposed, even with insulation. We had a garage convertion like that that was so cold in winter it was totally unusable. We insulated the walls, but the biggest difference was insulating the ceiling and putting a pitched roof over the flat one that was there (though I think the insulation was what did it) and most important, we put rigid insulation into the floor - which was a slightly raised wooden floor over concrete.

We recently took up the (wooden) floor of a small conservatory extension (mostly glass) which opened into the house (no door) and put in rigid insulation and the difference is amazing. We have also put a small rad in that area. Previously the cold caused a convection effect which made it seem as though there was a draught, but that has gone.

Well, the reality is that the two unplastered walls are less than a foot from boundary walls so in terms of shelter they are very sheltered. Very little rain falls on the walls, although that's not to say they are always dry. I'm sure moisture does get through.

The floors have that 6/7 inch insulation under the concrete over a red membrane barrier.

AlanD

if I wanted to get professional help to sort out my problem, someone who would come in and with good engineering knowledge figure out and come up with a solution, what sort of a person should i look for.

I've had builders in and those insulation fitters. The best they can do is finger in the air type guessing which i can do myself.

I need someone who can just sort it.

Any ideas?

muffler

Have you considered getting the cavity walls pumped and the attic areas insulated? If the house was built pre 2006 you would get a grant and would be out very little.

From reading your posts the problem to me appears to be in the bedroom although I have to say Im puzzled as to why the testing you had done didn't show up more weak spots to correlate with your description of the problems.

The mainhouse was the sieve!! But the mainhouse is warm

I dont understand that quote. Are you saying that the bedroom is 5 degrees colder than the rest of the house but the house is leaking more heat in your opinion?

AlanD

What i mean is that when the blower test was done, the main house had more holes in it than the extension. Definitely leaking more air overall.

I asked the insulation guy about pumping the walls. There isn't enough space in the cavity for it to work. Only about 10mm either side of insulation, if even. He reckoned the bead would not settle

So this morning i had the heating on for a bit. Main house was at about 19 degrees, but that new bedroom was about 14 degrees. If you touch the walls they are ice cold.

muffler

AlanD wrote: »

I asked the insulation guy about pumping the walls. There isn't enough space in the cavity for it to work. Only about 10mm either side of insulation, if even.

Poor construction as you should have had at least a minimum of 40mm residual air cavity which believe it or not is probably a contributing factor to a certain degree (no pun intended )

Thermal imaging would show all the differential wall/floor/ceiling temperatures. There's nothing that you can do with the floor (you can actually but your into quite substantial works) so you need to look at the walls and ceiling/attic.

Perhaps consider internally insulating the walls and improving the attic insulation.

MicktheMan

AlanD wrote: »

Only about 10mm either side of insulation, if even.

This could very well be your problem as Muffler has said. If the cavity insulation is not tight against the internal block leaf then the insulation is largely ineffectual due to thermal looping in the cavity. 10mm is a huge gap in this context!
Why this isn't an issue in the dining area may be due to a difference in the ratio of volume to exposed wall area between to two areas.

There may also have been a difference in workmanship by the block layer due to ease of access when walls were built. Are you 100% sure that there is insulation in the bedroom wall cavities? Did the thermogtapher not investigate further what was causing the thermal difference?

AlanD

muffler wrote: »

Poor construction as you should have had at least a minimum of 40mm residual air cavity which believe it or not is probably a contributing factor to a certain degree (no pun intended )

Thermal imaging would show all the differential wall/floor/ceiling temperatures. There's nothing that you can do with the floor (you can actually but your into quite substantial works) so you need to look at the walls and ceiling/attic.

Perhaps consider internally insulating the walls and improving the attic insulation.

That makes sense alright. I think they cavity is about 110mm with 100mm of insulation bang smack in the middle.

When i was with the thermal imaging guy we could easily see how cold the wall was, he thought that cold air was getting on the inside of the insulation rendering it useless, but wasn't sure.

What is the thinnest most effective internal insulation you can get?

AlanD

MicktheMan wrote: »

This could very well be your problem as Muffler has said. If the cavity insulation is not tight against the internal block leaf then the insulation is largely ineffectual due to thermal looping in the cavity. 10mm is a huge gap in this context!
Why this isn't an issue in the dining area may be due to a difference in the ratio of volume to exposed wall area between to two areas.

There may also have been a difference in workmanship by the block layer due to ease of access when walls were built. Are you 100% sure that there is insulation in the bedroom wall cavities? Did the thermogtapher not investigate further what was causing the thermal difference?

I know that the block layer was meticulous in how he laid blocks and put in insulation. I was here the entire time and in the evening i used to measure everything just in case.

Ironically, the one thing i asked the builder to provide me with was a warm extension. I didn't know enough at the time to know if what he was doing was right or wrong. No matter, we need go fix it now.

LK_Dave

When the thermal imaging guy pointed out the cold spots in the external leaf were these from either the external two leafs (nonplastered) adjacent to the boundary wall or the exposed (plastered) wall?

I do not want to compromise your home security but could you take a picture of the extension and mark where the thermal imaging pointed out where the cold spots were? Also a pic of one of the unplastered walls.

I think the issue lays with the unplastered wall....may have a terminal bridge. Are there any signs of damp in the building?

I'm leaning towards the unplastered wall because although it may not be directly getting a lot of rain, we do live in a damp climate and a lot of water will pass down a 1 foot gap plus the sun will not help to dry out the wall.

AlanD

LK_Dave wrote: »

When the thermal imaging guy pointed out the cold spots in the external leaf were these from either the external two leafs (nonplastered) adjacent to the boundary wall or the exposed (plastered) wall?

I do not want to compromise your home security but could you take a picture of the extension and mark where the thermal imaging pointed out where the cold spots were? Also a pic of one of the unplastered walls.

I think the issue lays with the unplastered wall....may have a terminal bridge. Are there any signs of damp in the building?

I'm leaning towards the unplastered wall because although it may not be directly getting a lot of rain, we do live in a damp climate and a lot of water will pass down a 1 foot gap plus the sun will not help to dry out the wall.

The coldest walls were the two that were unplastered with a boundary wall outside of each of them.

I think the fact that the internal walls are cold would suggest some sort of cold bridging for sure.

Just the note too that the top couple of feet of each of the walls is plastered. On the thermal camera you could see where the temp changed. The entire wall below this line was cold. Saying that though, the temp above the plaster line wasn't much warmer.

If, the external walls were plastered, would the blocks and insulation inside it dry out?

I'll take some pics to help alright.

LK_Dave

AlanD wrote: »

If, the external walls were plastered, would the blocks and insulation inside it dry out?

It will take time but yes...eventually.

However the walls should not only be plastered they should also (in time)be painted. There is now on the market an insulating paint. I was it discussed here on the boards at one point. I have never used it but here is the link http://www.thermilate.com/store/ But please note the entire wall should still be plastered.

muffler

AlanD wrote: »

he thought that cold air was getting on the inside of the insulation rendering it useless, but wasn't sure.

That would indeed be a major factor.

AlanD wrote: »

What is the thinnest most effective internal insulation you can get?

You need to be looking at something like this. Loosing a couple of inches on floor space is a small rice to pay for the increased heat retention.

AlanD wrote: »

The coldest walls were the two that were unplastered with a boundary wall outside of each of them.

I think the fact that the internal walls are cold would suggest some sort of cold bridging for sure.

AlanD wrote: »

If, the external walls were plastered, would the blocks and insulation inside it dry out?.

The fact that the walls are not plastered is also a contributing factor. Every layer is important in it's on right. Compare it with putting on an extra layer of clothing in the winter. No matter how thin the extra layer is it's still contributing towards heat retention.

AlanD wrote: »

On the thermal camera you could see where the temp changed. The entire wall below this line was cold. Saying that though, the temp above the plaster line wasn't much warmer.

Warm air rises so that would have accounted why the top was showing that little bit warmer.

AlanD

Some pics of the back wall

IMG_0106.jpg

IMG_0109.jpg

IMG_0110.jpg

IMG_0107.jpg

IMG_0108.jpg

caesarthechimp

AlanD wrote: »

What sort of the person should I be looking for and could you recommend anyone?

You already had the guy in.....

AlanD wrote: »

When i was with the thermal imaging guy we could easily see how cold the wall was, he thought that cold air was getting on the inside of the insulation rendering it useless, but wasn't sure.

and he told you what the problem was...

Having no render is not the problem; cold air sinks by convection,
coincidentally to the place where the render is missing.
You didnt say what the 100mm of insulation was; Polystyrene?
Try drilling a series of holes from the inside near the wall plate and injecting in expanding polyurethane foam. The stuff in aerosol cans would do for a small area. If you can stop a curtain of warm air rising between the inside leaf wall and the insulation, and escaping out at the top, you may be sorted.

AlanD

Ok well that's good so.

But then what is stumping me is how the cold air is getting inside the insulation. The insulation goes to the top of the wall and the walls are capped too.

Not a bad idea with the spray stuff. Not sure how effective or complete the solution would be though.

Oh, insulation is polystyrene.

caesarthechimp

AlanD wrote: »

The insulation goes to the top of the wall and the walls are capped too.

To get the insulation to butt tightly against the cavity closer block would require very precise measuring and cutting of the top course of polystyrene batts. I have not seen a blocklayer cut insulation except by hacking at it with a trowel.
The batts are not airtight at the joints, unless siliconed which is very unusual. Therefore if not tight against the inner leaf wall, a convection current can be set up , air rising on the inside face of the batts, crossing at the top, and falling down the outside face, cooling, then percolating back through the joints near the bottom.

We have a longstanding problem with "workmanship" and insulation in Ireland, because most brickies are subcontractors, and they get paid by the number of blocks they lay; they get nothing for fiddling around with insulation.

LK_Dave

Enrate has given you some good advice here but I would disagree with his assertion that the lack of plaster/render is not a problem.

Enrate wrote: »

Having no render is not the problem;

The terminal imaging scan identified these parts of the wall to be cold areas. Correct? Cold areas caused by convection, in my experience, appears as a band/level at the bottom of the wall. But I stand to be corrected on this.

Looking at the last picture, damp patches are visible on the boundary wall. If they are there you can be dam sure that they are also on the extension wall. As I stated before, these areas probably never totally dry out as the suns’ rays can’t reach them. Damp in our climate will cause cold. Note concrete blocks and mortar are porous unless they are chemically treated. It would only take one polystyrene sheet to have a hole or to be setting askew on a block tie to be the culprit. But since the terminal image reported the issue on both walls I still think the lack of plaster/render to be the issue. You have to get this seen to.

It is a good idea to seal the terminal envelope by drilling holes inside just below where the ceiling meets the wall as suggested by Enrate but you will have to drill a lot of holes along a line a couple inches apart to inject the foam. It will be trial and error to figure out how far apart the injection holes should be. I would suggest drill three or four say four inches apart and inject into the middle holes first and see if the foam reaches the other ones. As I said, trial and error!! But before you do that, try to access the cavity vial the crawl space in the attic (I know it will be tight, but in this case it is better to measure twice before you cut so to speak). The object here is to try to seal the internal leaf to the polystyrene sheet to restrict convection.

BryanF

Beware of internal insulation, it is now understood that a calculation is required to determine where moisture will condense in the wall. I would recommend you consider external insulation, although I appreciate the site constraints. You mentioned the walls are cold, the thermal looping suggestion is probably correct, but are there any damp patches/mould? This will not disappear with dry-lining but simply be hidden, saying up the problem for a later date.

Also take down the internal plaster board, ensure the insulation is fitted correctly, consider lowering the ceiling to increase the insulation and provide an air-tight membrane. (I am presuming there are vents in windows and wall?) I would recommend Gutex wood fibre board with taped joints and re-plasterboard.

This is the builders fault; he did not comply with building regulations. The blame also lies with your Architect/Engineer for allowing this work to go ahead.

AlanD

Enrate wrote: »

To get the insulation to butt tightly against the cavity closer block would require very precise measuring and cutting of the top course of polystyrene batts. I have not seen a blocklayer cut insulation except by hacking at it with a trowel.
The batts are not airtight at the joints, unless siliconed which is very unusual. Therefore if not tight against the inner leaf wall, a convection current can be set up , air rising on the inside face of the batts, crossing at the top, and falling down the outside face, cooling, then percolating back through the joints near the bottom.

We have a longstanding problem with "workmanship" and insulation in Ireland, because most brickies are subcontractors, and they get paid by the number of blocks they lay; they get nothing for fiddling around with insulation.

I know for a fact that the insulation is not siliconed together. It had a tongue and groove type setup so they slotted in to each other as the walls went up.

What I know aswell is that there is nothing else in there apart from damp proof membrane, two walls and insulation plus a block cap. There is nothing at all to stop the cold bridging.

I didn't know much about any of this stuff when building and neither did the builder!

We only had an architect draw plans and that's all he was paid for. We put our trust in the builder after that.

AlanD

LK_Dave wrote: »

Enrate has given you some good advice here but I would disagree with his assertion that the lack of plaster/render is not a problem.


The terminal imaging scan identified these parts of the wall to be cold areas. Correct? Cold areas caused by convection, in my experience, appears as a band/level at the bottom of the wall. But I stand to be corrected on this.

Looking at the last picture, damp patches are visible on the boundary wall. If they are there you can be dam sure that they are also on the extension wall. As I stated before, these areas probably never totally dry out as the suns’ rays can’t reach them. Damp in our climate will cause cold. Note concrete blocks and mortar are porous unless they are chemically treated. It would only take one polystyrene sheet to have a hole or to be setting askew on a block tie to be the culprit. But since the terminal image reported the issue on both walls I still think the lack of plaster/render to be the issue. You have to get this seen to.

It is a good idea to seal the terminal envelope by drilling holes inside just below where the ceiling meets the wall as suggested by Enrate but you will have to drill a lot of holes along a line a couple inches apart to inject the foam. It will be trial and error to figure out how far apart the injection holes should be. I would suggest drill three or four say four inches apart and inject into the middle holes first and see if the foam reaches the other ones. As I said, trial and error!! But before you do that, try to access the cavity vial the crawl space in the attic (I know it will be tight, but in this case it is better to measure twice before you cut so to speak). The object here is to try to seal the internal leaf to the polystyrene sheet to restrict convection.

Would I see damp patches on the internal walls two years down or could it take longer?

Without a doubt I will definitely plaster the wall and I like the look of that insulation paint linked above.

But one option I had considered was to fill the entire cavity between boundary wall and extension wall with bead insulation (pumped) and roof the gap so it's totally sealed (not in that order, but whatever is most appropriate). So, this would give about a foot of insulation, but possibly this could get wet if I didn't have it damp proofed.

As an alternate, I might get the insulation pumpers out again and do a meticulous investigation inside the walls with camera's. So perhaps they could pump the walls to a certain extent to prevent the cold air from circulating as it seems that is a major problem. Then plaster it on the outside.

AlanD

BryanF wrote: »

Beware of internal insulation, it is now understood that a calculation is required to determine where moisture will condense in the wall. I would recommend you consider external insulation, although I appreciate the site constraints. You mentioned the walls are cold, the thermal looping suggestion is probably correct, but are there any damp patches/mould? This will not disappear with dry-lining but simply be hidden, saying up the problem for a later date.

Also take down the internal plaster board, ensure the insulation is fitted correctly, consider lowering the ceiling to increase the insulation and provide an air-tight membrane. (I am presuming there are vents in windows and wall?) I would recommend Gutex wood fibre board with taped joints and re-plasterboard.

This is the builders fault; he did not comply with building regulations. The blame also lies with your Architect/Engineer for allowing this work to go ahead.

There is no internal plaster board, just plastered walls.