Moisture Issue in Loft New Build

[Grzyb]

Those comments on their own, suggest to me excess moisture being generated inside the house, plus lack of adequate ventilation. Basically - drying clothes in the house, boiling pots without lids, baths and showers without turning extract fans on, or ventilating afterwards. The moisture in the house, will also find it's way into the loft and condense on the coldest part - the roof.

A humidity gauge might be helpful, to confirm it.

Will see what sort of Prices they are, but I'm sure the Persimmon Inspector will have one, on the 14th.....

 

[Grzyb]

"Responsibility" is probably a better work than "blame".

But yes from the builder's perspective, removal of insulation to add boarding, ie reducing the performance of the ceiling insulation and thus allowing more warm air into the loft to then condense, could be deemed a contributory or single factor.

But that's not to say that there are not other issues - eg have foil backed plaster boards been used where they should have been or should the roof void be able to deal with this regardless, so you need expert advice on this.

Unfortunately, the majority of us "trust" these Companies to do the right thing & Construct properties to a very high standard, I'm not saying that they put Profit before Customer welfare, but.....

I will get Professional Advice, If required....

I just want a fair crack @ the Whip, & If I made a mistake in recommending the Boarding, I will hold my hand-up & take it on the Chin....If they have made any mistakes, I just want them to meet me half-way to rectify it.....The last thing I want is confrontation & to sour the taste of my Daughter's First New Home....Mistakes do happen, I understand that...hopefully it can be resolved amicably...

 

[JP_]

Is this the latest way to design these roofs, with a breathable (goretex esque) membrane acting as a large surface area ventilation through the tiles?

I think that is the idea, but I've not seen it actually work. I don't think the membranes breathe enough to let moisture escape.

 

[Harry Bloomfield]

But yes from the builder's perspective, removal of insulation to add boarding, ie reducing the performance of the ceiling insulation and thus allowing more warm air into the loft to then condense, could be deemed a contributory or single factor.

The OP hasn't suggested he removed insulation, rather that he added stand-offs upon which the boards were added - perhaps the OP could comment on this?

I would suggest the boards would help limit the transfer of moisture from the house to the loft, rather than make it worse, as it would help slightly to retain the warmth below it.

 

[JP_]

How Did You Sort Yours Out in the End?? If you don't mind me asking??

Read more: https://www.diynot.com/diy/threads/moisture-issue-in-loft-new-build.582613/#ixzz7EMPuh7RQ

I managed to get Felt Lap Vents in where sheets of membrane overlay each other, I also just shoved random bits of solid insulation (just because it is light and I had loads laying about) to create some openings.

I bought a load of soffit vents, but never got round to installing, mostly because all the other vents helped it dry out.

My loft was soaking. The felt was covered in water, and in winter, ice. Whenever I opened the loft hatch I got rained on. Mould was forming on everything in the loft, so it was only a matter of time before fungus and rot came along.

I'll take a photo, bear with ...

 

[^woody^]

The OP hasn't suggested he removed insulation, rather that he added stand-offs upon which the boards were added - perhaps the OP could comment on this?

I would suggest the boards would help limit the transfer of moisture from the house to the loft, rather than make it worse, as it would help slightly to retain the warmth below it.

He said he has boarded it, does not mention using legs. Compressing insulation reduces its performance.

 

[^woody^]

I managed to get Felt Lap Vents in where sheets of membrane overlay each other, I also just shoved random bits of solid insulation (just because it is light and I had loads laying about) to create some openings.

I bought a load of soffit vents, but never got round to installing, mostly because all the other vents helped it dry out.

My loft was soaking. The felt was covered in water, and in winter, ice. Whenever I opened the loft hatch I got rained on. Mould was forming on everything in the loft, so it was only a matter of time before fungus and rot came along.

I'll take a photo, bear with ...



View attachment 253358 View attachment 253359 View attachment 253360

Typically, membranes should be fitted with a sag and not taught. This provides ventilation via the laps.

 

[CBW]

We have a similar issue, Morris homes basically said, it’s condensation from having the heating on - utter ballcocks if you ask me. We have no eaves ventilation and this “breathable” membrane shoite, which IMO is the problem. We added (at our expense) 2 roof tile vents, but never got round to installing 2 on the other side.

 

[Harry Bloomfield]

He said he has boarded it, does not mention using legs. Compressing insulation reduces its performance.

The OP wrote 'Crux of the Matter is we Contacted Persimmon, the House Builder & they are coming out to investigate on the 14th, we told them of the boards & they have already said that if the boards are the issue, then they will wash their hands of any liability, only Part of the Loft has been boarded & the boarding is on Stilts so nothing is really "enclosed"....'

I would interpret 'stilts' as legs, or stand off's, but perhaps the OP could enlarge on that point?

 

[JP_]

it’s condensation from having the heating on

It is amazing the bullshit builders tell you. My builder actually said the condensation was caused because there was so much insulation in the loft, it was getting cold, so the solution was to remove some of the insulation. Complete nonsense.

A builder that came round to remove a chimney saw them and said it was common these days to have to install flap vents as so many new builds are built like that, with condensation problems. In fact, in my 2002 Barratt's house, the roof had vents in to stop condensation. It's as if somewhere in the past decade builders have forgotten why lofts need to be ventilated.

 

[BlueLoo]

The loft flooring will have absolutely nothing to do with the condensation in the loft apart from make it better, not worse as it stops airflow from below, not encourage it.
What can happen if it's just shoved on top of the insulation and joists is exactly that, the air gets trapped and you get moisture under the boards themselves.

I am going to be putting loft boards in my attic soon and i've done a fair bit of investigation on this issue. From what i can tell, the air gap under the board is a requirement. I'll be peforating the boards when i do do this to help airflow somewhat although its probably overkill.

Reading this thread, the loft condensation is a membrane issue as noted by Chris and other above.

The room condensation is only related to the above in so much that new build houses are designed to by somewhat airtight and do not suffer high humidity anything like as well as the traditional house build. Couple this with, i imagine, zero instruction from the house builder as to how to operate the house correctly and you have multiple condensation issues in many parts of the house.

My opinion on the above only (see Sig.)

 

[BlueLoo]

It is amazing the bullshit builders tell you. My builder actually said the condensation was caused because there was so much insulation in the loft, it was getting cold, so the solution was to remove some of the insulation. Complete nonsense.

A builder that came round to remove a chimney saw them and said it was common these days to have to install flap vents as so many new builds are built like that, with condensation problems. In fact, in my 2002 Barratt's house, the roof had vents in to stop condensation. It's as if somewhere in the past decade builders have forgotten why lofts need to be ventilated.

Plumbers, electricians, builders, etc, etc, all trades seem to be low on training , standards, qualifications and professional pride these days.

I don't trust any of them, no matter how good they think they are, the "educated" ones especially....

 

[Grzyb]

The OP hasn't suggested he removed insulation,

Correct, No Insulation has been removed, All still in Place as far as I know....I didn't actually put the Boards-In, They were done by a Professional Loft Fitting Company, took them about a couple of hours....

rather that he added stand-offs upon which the boards were added - perhaps the OP could comment on this?

Here is the Original Installation Video

https://www.dropbox.com/s/0h37yve8uop8c93/Loft Boarding.mp4?dl=0

I would suggest the boards would help limit the transfer of moisture from the house to the loft, rather than make it worse, as it would help slightly to retain the warmth below it.

 

[BlueLoo]

The boards are nothing to do with this issue. don't let the builder tell you otherwise.

 

[Harry Bloomfield]

You still didn't answer the question - Are the boards laid flat down, or set on some sort of leg or stand off, raising them clear of the insulation?