Condensation in Lofts and Roof Spaces

SIRT

I have just finished ventilating the loft of the 8th property this month, that has had recent loft insulation installed without any form of ventilation which had led to severe condensation problems.

I really want to lobby the Government about this as the Carbon Emission Reduction Target grant scheme, does not allow any funding to cover the cost of ventilation and many people simply cannot afford to do the job properly and allow the insulation teams to install quick fix solutions that fit their budget, but put their roof and contents at risk. Some don't have anything at all.

I would like to hear from anyone who has experienced the problem of condensation in roof spaces and what remedies were used and whether they did in fact get any assistance from a grant for this. The number of hits and responses will help get the message to the right department.

Thank you in anticipation.

Gloomendoom

Mine has nothing at all... apart from all the gaps! I keep a temperature and humidity sensor up there which feeds into a weather station downstairs.

That way I can monitor what is happening.

wildbri

Hi, I have owned and lived in a detached bungalow for 37 years, I used to store a lot of stuff up there like everyone else. A couple of years ago I decided to empty the roof space ready for the extra insulation provided for the over sixties. This was installed and I was very pleased. During the first winter I saw water dripping from the soffit board, I climbed into the roof space thinking I had a leak and found that the roof felting was dripping with what I presumed was condensation. The roof has an air brick on either cable end but they seem small for a large space.

What I hope is a cure was very simple and inexpensive to me, as I am a practical person. I drilled a series of large round holes in the soffit and used push in vents.

It is a concern as this condensation could badly damage timbers and ceiling plaster boards especially in older properties.

Regards bri

iamcornholio

Condensation is not a problem in itself, and does not damage timber just by it forming in the loft. It only becomes a problem if mould or fungi takes hold, but this will require a very specific set of circumstances.

Many (most?) lofts get condensation on the sarking during the winter months and there are no problems at all

Do you think it is a bit alarmist to imply that the presence of condensation automatically means some major problem?

The simple solution is to open the felt laps, which assists with lowing humidity and this also allows any run-off to run down the sarking and out through the lap, rather than run all the way down the sarking to dampen the insulation near the eaves

Joatmojo

The simple solution is to open the felt laps, which assists with lowing humidity and this also allows any run-off to run down the sarking and out through the lap, rather than run all the way down the sarking to dampen the insulation near the eaves[/QUOTE]


The above quote (and the rest that goes with it!) is probably the worst possible piece of advice anyone could give for controlling ongoing condensation in roof spaces.

Of course it would probably work in the short term; if you were prepared to sit up there in the loft managing the effects of storm driven rain and snow quite regularly or constantly directing dribbling condensation - not forgetting handling the dangers of wind-uplift and infestation! But as a permanent job for the long term it is absolutely barmy advice, goodness knows what the motive for such nonsense is.

Ask any responsible professional who is only partly familiar with good building practices in this area and they will catagorically tell you the same.

Not only does it drive a horse and cart through acceptable standards it is also downright irresponsible to suggest such a thing, period.

Either tell us it was a joke, or do a bit of research and come back and quote the source where it says your information is officially approved practice.

Joatmojo
('the truth will out')

brig001

We had bad condensation after our loft was insulated, but it was caused by wind blowing steam from the bathroom extractor fan into the soffit vent. Since the vent is a continuous slotted section, I covered about a 2 metre length with tape over where the fan exited the wall. No problems since.

Brian.

iamcornholio

Joatmojo wrote: »

Either tell us it was a joke, or do a bit of research and come back and quote the source where it says your information is officially approved practice.

Oh dear. Are you still smarting from your previous bit of "childish tit-for-tat"?

Presumably you have gained even more qualifications since your last posts, but none it seems in common sense.

Opening the felt laps vents the roof void, in exactly the same way as fitting proprietary roof vent tiles does. Rain will not enter, snow wont come through(!!!) and no storm will rip the roof off

Joatmojo

Quite right Andrew B, a perfectly valid observation well put; but dont be misled by dodgy so called 'professional' advisers and 'cowboy' practices.

Many, many people do their own thing and find numerous ways around a lot of diverse problems - and why not! Unless they know exactly what they are doing though, the general public does not usually mess about with electrics or plumbing; those trades are tightly regulated anyway. In contrast however housholders are mainly left to their own devices under the DIY mantle.

There are two avenues you can take, do a short term quick-fix botch up, or a more stable permanent job as approved by the industry. Simple as that. As long as you understand the consequences of sometimes taking bad advise, or just going for a temporary improvisation, the rest is up to you - that is the value of these types of forum; you may hear all sorts of things from all sides of the argument.

Older buildings are old because they were built sympathetically and skillfully, some very ancient ones were built without benefit of footings, dampproof course or even smoke stacks, etc. The building game started as a hit and miss affair which evolved over centuries, during which time we have adapted and improved our lot. Uninsulted roofs were the norm, no problem, anything that blew in dried out quite rapidly and there wasn't much harm to be done anyway, people were sturdier in those days as were their very basic belongs.

As living conditions improved the underside of imortant buildings were insulted with amongst other things highly permeable lime/hair mortar tiering/torching and then, eventually, 'underfelt'.

Certainly there are occasional circumstances where it seems roof insulation may not even be needed but it is there for a very good reason, ask 'any' underfelt manufacturer what rules must be met before their products are deemed fit for purpose when fixed properly- ask them about opening up the overlap without protection.

Lessons have been learned through experience, there are standards to be met, but hey! we live in a throw away society, easy come easy go lets get round it somehow and good luck to you; then of course there is always the one trying to justify substandard activities.

In comparison, I doubt people would destroy their homes damp-courses quite so readily, even though that may not have the potential to cause so much future damage.

This topic covers something that has been a great part of my life - therefore in all good faith, I am having a crack at offering genuine, unambiguous advise.

Joatmojo

dan1992_2

My grandparents had loft insulation installed using a grant scheme last year – they weren’t told about ventilation. Last Christmas when my uncle went in their loft to get some old photo’s he found them soaking wet and many were ruined. He called back the installers, who said that they had fitted ventilation devices with springs that opened the felt but these appeared to have failed and had fallen out. They apologized and put some polystyrene wedges in the felt joints. This worked until the summer, when they had a massive swarm of bees enter the roof and build a nest near one of the openings. When they got a pest control officer to deal with this, he referred them to building control who insisted the wedges were removed immediately as opening a sealed roof was in breach of part C? of the building regulations?. They now have condensation forming again and are waiting for the original installer to come back and put correct ventilation in. I hope this helps SIRT and I would be interested to know what method you use?

Hopeful_5

An interesting, if worrying, thread .

Would this condensation happen if a roof is covered with Tyvek breathable felt? How breathable is it - are air vents in the eaves necessary?

Thanks for any replies.

Hope

Dry_Rot

Hi All,

Transiant condensation will happen in roof voids and is only a problem if it is excessive and/or persistant. Roofs get heated quickly and cool fast and this fluctuation will inevitably cause the odd bit of condensation.

For advice have a look at this BS5250 ammendment

http://www.glidevale.com/downloads/Condensation_Control_BS5250_White_Paper.pdf

Dry Rot