Condensation in a new build

creedp

Hi

I have moved into a new build in the last 3 weeks which has taken a full 18 months to complete. The walls/roof/windows were completed by December. All internal plastering completed by March and the finished floors finished (after a tortorous delay)in June. It has UFH and MHRV. It has an airtight test result on 2.64. Before I moved in there was no condensation to be seen anywhere in the house. However, since I've moved in I have noticed condensation along the glass perimeter of the windows and doors and on the handles of the windows and external doors. The rest of the house seems fine, i.e. walls etc. I have asked the MHRV guy to come back and check the system out as I thought (probably nievely again) that the MHRV would keep the place condensation free. Because it has gotton worse I have take to using a dehumifier and find that it is removing about 4 litres of water over 24hrs. This seems very excessive to me. Could this problem relate to the house still drying out? Should the MHRV system be doing a better job in shifting it?

tred

creedp wrote: »

Hi

I have moved into a new build in the last 3 weeks which has taken a full 18 months to complete. The walls/roof/windows were completed by December. All internal plastering completed by March and the finished floors finished (after a tortorous delay)in June. It has UFH and MHRV. It has an airtight test result on 2.64. Before I moved in there was no condensation to be seen anywhere in the house. However, since I've moved in I have noticed condensation along the glass perimeter of the windows and doors and on the handles of the windows and external doors. The rest of the house seems fine, i.e. walls etc. I have asked the MHRV guy to come back and check the system out as I thought (probably nievely again) that the MHRV would keep the place condensation free. Because it has gotton worse I have take to using a dehumifier and find that it is removing about 4 litres of water over 24hrs. This seems very excessive to me. Could this problem relate to the house still drying out? Should the MHRV system be doing a better job in shifting it?

How long did you late the floors dry out?. Is it all over, or is there any main areas that are more effected than others?

creedp

tred wrote: »

How long did you late the floors dry out?. Is it all over, or is there any main areas that are more effected than others?

The finished floors were poured in late June and I let them dry for 2 months before they were covered with semi-solid floor boards upstairs (screed 75mm) Downstairs the majority of the surface is polished concrete (screed 100mm before polishing) which onviously remains uncovered. I kept the UFH off for a number of weeks after laying the floors and then built it up gradually but the house was always warm, i.e. between 19 and 20c. I din't want to heat it any further as I was afraid of plaster/screeds cracking due to forced drying. Maybe, in retrospect, this was a mistake.

At the moment the worst affected area is the ensuite but there is moisture to a lessor or greater around the frames (timber) of every window in the house. As well as that the metal handles of the external doors are saturated with condensation.

As I said Im getting the MHRV guy back to check over the efficiency of the Unit but I suppose Im trying to understand is this something that can happen with new houses or is it associated with something I should worry about?

tred

creedp wrote: »

The finished floors were poured in late June and I let them dry for 2 months before they were covered with semi-solid floor boards upstairs (screed 75mm) Downstairs the majority of the surface is polished concrete (screed 100mm before polishing) which onviously remains uncovered. I kept the UFH off for a number of weeks after laying the floors and then built it up gradually but the house was always warm, i.e. between 19 and 20c. I din't want to heat it any further as I was afraid of plaster/screeds cracking due to forced drying. Maybe, in retrospect, this was a mistake.

At the moment the worst affected area is the ensuite but there is moisture to a lessor or greater around the frames (timber) of every window in the house. As well as that the metal handles of the external doors are saturated with condensation.

As I said Im getting the MHRV guy back to check over the efficiency of the Unit but I suppose Im trying to understand is this something that can happen with new houses or is it associated with something I should worry about?

Keep the dehumidifer going for a week and see, move it around if u can.
Be what ur saying above, u should be well dry, i would have thought.
My floor screed dried fairly naturally, not much heat at all.

creedp

tred wrote: »

Keep the dehumidifer going for a week and see, move it around if u can.
Be what ur saying above, u should be well dry, i would have thought.
My floor screed dried fairly naturally, not much heat at all.

That's what I thought also. That's why I was very surprised to see this amount of condensation on the windows. I will keep the dehumidifier on for a while to see if it improves things. I have it upstairs during the day and move it downstairs at night. Thanks

tred

creedp wrote: »

That's what I thought also. That's why I was very surprised to see this amount of condensation on the windows. I will keep the dehumidifier on for a while to see if it improves things. I have it upstairs during the day and move it downstairs at night. Thanks

Your HRV is hardly piped arseways is it!! ?? ...pushing the wet air in!!.
Sounds crazy...check all that out as well!!... let us know how you get on

creedp

tred wrote: »

Your HRV is hardly piped arseways is it!! ?? ...pushing the wet air in!!.
Sounds crazy...check all that out as well!!... let us know how you get on

Is that possible? I know that the wet areas, i.e. the kitchen/bathrooms etc have extract vents and certaintly they are in extract mode as you can feel/hear the air being extracted. One thing I never fully checked out is if there is condensate dripping from the condensate outlet. I have to say I never actually noticed anything dripping from this pipe and I would have thought with the high humidity inside the house that there should be a steady drip/flow from this pipe. I'll see what happens on Thursday.

Thanks

kboc

tred wrote: »

Your HRV is hardly piped arseways is it!! ?? ...pushing the wet air in!!.
Sounds crazy...check all that out as well!!... let us know how you get on

if you put your hand up to the extracts and inlet vents you should feel the air pushing out and coming in

gears

tred wrote: »

Your HRV is hardly piped arseways is it!! ?? ...pushing the wet air in!!.
Sounds crazy...check all that out as well!!... let us know how you get on

Thats not possible. A HRV cant pump in "wet air" you would just be extracting from living areas and ventilating wet rooms, any moistue would still condense in the heat exchanger. The air would still flow from room to room but what might happen is that as you are not extracting directly from wet rooms you might find condensation forming before it has a chance to be removed.

OP. If you're not having any joy from your installer I've pm'd a name of someone who could help you out.

tred

gears wrote: »

Thats not possible. A HRV cant pump in "wet air" you would just be extracting from living areas and ventilating wet rooms, any moistue would still condense in the heat exchanger. The air would still flow from room to room but what might happen is that as you are not extracting directly from wet rooms you might find condensation forming before it has a chance to be removed.

OP. If you're not having any joy from your installer I've pm'd a name of someone who could help you out.

I was thinking outside the box, if someone had mixed up an exit pipe to a room instead!...not logical i know...but if the house is good and dry, as it soudns it should be, where is the moisture coming from?. unless something has still not dried fully...

creedp

gears wrote: »

Thats not possible. A HRV cant pump in "wet air" you would just be extracting from living areas and ventilating wet rooms, any moistue would still condense in the heat exchanger. The air would still flow from room to room but what might happen is that as you are not extracting directly from wet rooms you might find condensation forming before it has a chance to be removed.

OP. If you're not having any joy from your installer I've pm'd a name of someone who could help you out.

Thanks for that I may take you up on that offer if things dont improve ...

creedp

tred wrote: »

I was thinking outside the box, if someone had mixed up an exit pipe to a room instead!...not logical i know...but if the house is good and dry, as it soudns it should be, where is the moisture coming from?. unless something has still not dried fully...

Well that's the Q I was considering ... is it common for new houses that should be well dried out to produce excess condensation such as this for a period after they being moved into?

sas

creedp wrote: »

Well that's the Q I was considering ... is it common for new houses that should be well dried out to produce excess condensation such as this for a period after they being moved into?

One of my friends recently moved into a PH. He did comment that for the first few weeks whenever heat was introduced (e.g. stove), quite alot of condensation was appearing on windows. Granted his HRV isn't running yet so that could be the issue.

Polished concrete was mentioned. I was told recently that the polishing process has a sealing effect on a slab and can greatly extend the drying time. No idea if it's true or not but it's possible.

Would it be worth taping a section (maybe 1 m2) of plastic sheeting to the floor for a day or 2 and see if there is condensation underneath when you then check it?

This is an "off the top of my head" idea, any damage it causes is not SASs fault!

If this was still happening in another months time, I'd be going a little further. For now though, I'd try not to worry.

Do-more

sas wrote: »

I was told recently that the polishing process has a sealing effect on a slab and can greatly extend the drying time. No idea if it's true or not but it's possible.

+1 This is very much the case that polishing concrete tightens the surface inhibiting moisture from escaping.

creedp

sas wrote: »

One of my friends recently moved into a PH. He did comment that for the first few weeks whenever heat was introduced (e.g. stove), quite alot of condensation was appearing on windows. Granted his HRV isn't running yet so that could be the issue.

Polished concrete was mentioned. I was told recently that the polishing process has a sealing effect on a slab and can greatly extend the drying time. No idea if it's true or not but it's possible.

Would it be worth taping a section (maybe 1 m2) of plastic sheeting to the floor for a day or 2 and see if there is condensation underneath when you then check it?

This is an "off the top of my head" idea, any damage it causes is not SASs fault!

If this was still happening in another months time, I'd be going a little further. For now though, I'd try not to worry.

Oops if that is the issue I have a lot of polished concrete (that in retrospect I regret because the floor was laid very badly and the polishing job couldn't remove some of this poor workmanship leaving different shades of finish depending on whether there was bump or a hollow in the finished floor!) about 100m2 in all and so it might be no surprise that the condensation issue is so widespread. Might try your tip SAS and see what happens. In any case I'll hold tough for a while to see if the problem lessens. At least I can say I have someting in common with a passive std house:) Thanks.

Thanks

creedp

creedp wrote: »

Oops if that is the issue I have a lot of polished concrete (that in retrospect I regret because the floor was laid very badly and the polishing job couldn't remove some of this poor workmanship leaving different shades of finish depending on whether there was bump or a hollow in the finished floor!) about 100m2 in all and so it might be no surprise that the condensation issue is so widespread. Might try your tip SAS and see what happens. In any case I'll hold tough for a while to see if the problem lessens. At least I can say I have someting in common with a passive std house:) Thanks.

Thanks

A new complication has arisen in this saga. The rcd tripped on a couple of occassions recently but I was always able to reset it no problem. Yesterday it tripped and I wasn't able to reset it so I went around and unlpugged everything and found out it was the MHRV unit that was the problem. When I looed more closely at the unit I found the floor underneath it was saturated and there is a slight watermark on the ceiling underneath it (its in the attic with insulation and an airtight membrane underneath it). I can only assume that the condensate drain was never connected and it has been spilling water onto the floor over the last couple of months. So now I don't have a MHRV unit and the condensation problem this morning was much worse requiring the opening of windows to reduce the problem.

A quick Q here how much water could have potentially leaked into the attic over the last couple of months and what kind of damage could this have done to wool insulation/membrane/insulated plaster board underneath? The attic has been floored with tongue and groove chipboard and the unit is located in a small enclosed room so very difficult to raise floor to find out what's going on underneath. I have contacted the installer again and now he says he can't come before Friday at earliest because his electrician in unavailable intil then. I don't know but customer service in this country, in my limited experience, has gone to the dogs!!

gears

I don't want to alarm you but if the drain was never fitted it would be many many L. The maximum amount of water air can hold at 20degC is about 17 grams so the air in an average house with average relative humidity could hold 5-10L of water multiply this by the number of air changes per day by days with out a drain on a HRV and it could be 100s of L.

creedp

gears wrote: »

I don't want to alarm you but if the drain was never fitted it would be many many L. The maximum amount of water air can hold at 20degC is about 17 grams so the air in an average house with average relative humidity could hold 5-10L of water multiply this by the number of air changes per day by days with out a drain on a HRV and it could be 100s of L.

That is exactly what I'm afraid of. I wonder would the airtight membrane act as a barrier to the water coming through the ceiling such that there could be a lot of water swilling around above it which simply hasn't got through to the ceiling? I suppose I'm am going to have to remove the unit and take up the floor to find out. What a mess!

Do-more

creedp wrote: »

That is exactly what I'm afraid of. I wonder would the airtight membrane act as a barrier to the water coming through the ceiling such that there could be a lot of water swilling around above it which simply hasn't got through to the ceiling? I suppose I'm am going to have to remove the unit and take up the floor to find out. What a mess!

I wouldn't touch it yourself until the supplier has been to have a look and put the onus on him to do it all, assuming he installed it, it's his baby after all.

creedp

Do-more wrote: »

I wouldn't touch it yourself until the supplier has been to have a look and put the onus on him to do it all, assuming he installed it, it's his baby after all.

The installer did all the installation work himself and therefore it was his responsibility to connect the condensate pipe to an external outlet or else advise that this job be done by others, the latter which he didn't do and the former is also looking dubious. I'm just hoping that the condensate pipe was connected but that it developed a leak such that only a minor amount of leakage ocurred!

Anyone with any knowledge about the properties of airtight membranes in retaining large volumes of water?

gears

Air tight membranes are breathable, that is they let water through but not air. Now we're talking about water in vapour form so I'm not sure what would happen if you tried to use it to hold back large volumes of liquid water but I would imagine it would still get through. Some water would also find it's way through any small holes or gaps in taping and also to the top of walls where the membrane was stuck on to and soak into that. You might get away with just having to replace some insulation in the attic but if there is a lot of water you could think about renting a wet/dry vac.

sas

Really sorry to hear that Creedp.

Hopefully its the lesser of the 2 evils and you'll have a nice dry home in a couple of weeks.

creedp

sas wrote: »

Really sorry to hear that Creedp.

Hopefully its the lesser of the 2 evils and you'll have a nice dry home in a couple of weeks.

Thanks Sas. This self build lark is just not worth it unless you are really clued in and pretty much live on the site especially when trades are at work or else you get the job properly supervised by an independent expert. This continuous uncovering of problems, many by fluke or they are uncovered when dealing with something else is simply not good for the ones sanity!

MicktheMan

creedp wrote: »

This self build lark is just not worth it unless you are really clued in and pretty much live on the site especially when trades are at work or else you get the job properly supervised by an independent expert.

Why oh why don't people realise this before they build?:(



At least this problem can be easily remedied.

refco

creedp wrote: »

. I have contacted the installer again and now he says he can't come before Friday at earliest because his electrician in unavailable intil then.
Not been smart but what the hell does an eletrician know about air flows and ducting or heat recovery
heat recovery is air conditioning and that is a trade of its own
would you ask a tiler or plumber to wire your fuse board
i dont blame the customer i blame the sales man that didnt have a clue about the system other than what he read in the brocher

creedp

refco wrote: »

creedp wrote: »

. I have contacted the installer again and now he says he can't come before Friday at earliest because his electrician in unavailable intil then.
Not been smart but what the hell does an eletrician know about air flows and ducting or heat recovery
heat recovery is air conditioning and that is a trade of its own
would you ask a tiler or plumber to wire your fuse board
i dont blame the customer i blame the sales man that didnt have a clue about the system other than what he read in the brocher

I didn't make myself clear here .. the reason the electrician was being brought along was that the unit was tripping the rcd so the installer wanted an electrician to have a look at this. He did arrive and of course the condensate drain was not installed. Difficult to comprehend. Because of this the condensate was dropping down into the casing of the unit and it was half full of water and it was this water that was causing the electrial problem. Funny thing was that not a whole lot of water to be found outside the unit which begs the question as to how efficient it was at removing moisture from the house. Anyway, the condensate drain has been installed and linked in to the DHW cylinder 'blow out' pipe and I can now see the condensate dropping from this pipe outside. Also the default unit speed has been increased for a couple of weeks to help dry out the house. The only downside to this is the extra noise at the inlets and extacts but thats a very small issue if it helps to solve the condensation problem. So hopefully this will sort the problem and the potential disaster appears not to have materialised!

refco

sorry for misunderstanding glad to hear you got problem resllved as regards moisture removal a lot of moisture will go directly out in the exhaust air as it wont all codensate across the heat exchanger depending on inlet and exhaust temperature differential

sydthebeat

creedp wrote: »

refco wrote: »

He did arrive and of course the condensate drain was not installed. !

jesus !!!!

creedp

refco wrote: »

sorry for misunderstanding glad to hear you got problem resllved as regards moisture removal a lot of moisture will go directly out in the exhaust air as it wont all codensate across the heat exchanger depending on inlet and exhaust temperature differential

Good point ... luckily for me the weather has been unusually mild up to now and this has probably helped. The current cold snap will probably increase the levels of condensate which would have been bad news if it continued to be deposited into the attic!! The other issue which helped retain a lot of the water in the unit was that the builder took it down at some point (it is hanging from the rafters) to do some slabbing work and put in back in the wrong position, (i.e. sloping the wrong way) which meant that any condensate that dropped into the unit casing stayed there rather than flowing out ... he won't be taking it down again!!

tred

creedp wrote: »

Good point ... luckily for me the weather has been unusually mild up to now and this has probably helped. The current cold snap will probably increase the levels of condensate which would have been bad news if it continued to be deposited into the attic!! The other issue which helped retain a lot of the water in the unit was that the builder took it down at some point (it is hanging from the rafters) to do some slabbing work and put in back in the wrong position, (i.e. sloping the wrong way) which meant that any condensate that dropped into the unit casing stayed there rather than flowing out ... he won't be taking it down again!!

Creedp, how you getting on. Have you resolved the issues with condensation?

creedp

tred wrote: »

Creedp, how you getting on. Have you resolved the issues with condensation?

The problem still exists but it would appear to be diminishing as some of the windows are now completely dry while some others have just the slighest hint of condensation along the bottom of the panes. The worst window is the ensuite but even that is not as bad as it was. Hopefully over the next couple of weeks the problem will be fully resolved.

At least the MHRV system seems to be operating OK now with the condensate drain in place. It has been stoked up temporarily to help with the drying out process. Im looking forward to it being returned to normal setting as at night it makes a fair racket at the moment.

tred

creedp wrote: »

The problem still exists but it would appear to be diminishing as some of the windows are now completely dry while some others have just the slighest hint of condensation along the bottom of the panes. The worst window is the ensuite but even that is not as bad as it was. Hopefully over the next couple of weeks the problem will be fully resolved.

At least the MHRV system seems to be operating OK now with the condensate drain in place. It has been stoked up temporarily to help with the drying out process. Im looking forward to it being returned to normal setting as at night it makes a fair racket at the moment.

good news. hopefully youll be sorted in January.