Need some help, live in bungalow built 19 years ago, bad condensation in loft frame work rearly wet,especially over integral garage.dried it out with dehumidifier but as soon as i switch it off the frames become wet again.Have six down lights in kitchen and one in bathroom both open in loft space, plus spin drier in garage and expeller in bathroom both vented on outside, also added two ridge vents but still wet frames in loft. p.s. please help.

reddave, January 2009

Quick money saving tip!!! Lap vents work by utilizing the air that comes up under the roof tiles. The amount of air will vary greatly on the type of tile fitted. For example, at one end of the scale, slate tiles will give very little air-flow if anything at all. Any type of pan tiles probably offer the most amount of air flow as they don't inter-lock. Instead of forking out money on lap vents you can achieve the same results by simply placing a thin wooden wedge in the joins (over-laps) of your roofing felt from inside your loft, and hence creating an air gap. Same principle.. Same effect.. Fraction of the cost.

Pete, June 2012

Every year this same question pops up, well here is and article I have written.
http://www.projects.toolvolt.co.uk/listing.php?id=1
Mick mentions that he has condensation forming between layers of insulation, now this confirms my article.
The insulation you in your loft will let an amount of heat thru over time. Now the problem Mick has is the heat is going thru the ceiling and the first layer of insulation, when the hot air hits the poly lining it will stop and hang around and because it cannot disperse, it will form into water droplets.
I think personaly that any poly cover insulation is very bad for your home, for the simple reason that when you lay the insulation out it will most likely not stay in contact with the ceiling the whole time and leave small air pockets where condensation will start to form.
In my opinion, the best insulation for this is Celotex or Kingspan. But beware, if you have inset lights in the ceilings, you must not use either of these products within half a meter as this sheets are flamable.

If you do not want to fit the round poly vents, then as Mr Fletcher says, Lapvent, very good products, though a very nice price tag too.

If you don't want to buy Lapvents, then pop over to www.toolvolt.co.uk and have a look at the Soffit ventalation kit. This will be online from 20 Nov 2010
And don't forget to check out the article as this a good set of instructions for the instaltion of this vents.
Many Thanks
Joe D
www.simplybuildbetter.co.uk

Joe Dybowski, November 2010

I had a similar problem, we purchased and fitted an amazing product called lapVent. Fitted from inside the loft in minutes, BRILLIANT!!!! www.lapvent.co.uk

J Fletcher, July 2010

Hi.
I have a problem in a rented property of mine.I have had the house in the family for over 10 years but rented out now.We have just had reported condensation damp occuring between the pink panther covered plastic type (which is fitted ontop of the yellow)and the normal standard yellow type in the loft.
This is in a terrace property which i think the cavity is failing a little but has not bothered it much over the years as i fit 4 x roof vents,the thing is there is damp not on the underside of the ceiling as the plasterboard is dry but only damp between the two differant tpyes.
This Pink Panther type was fitted for my tennant about a year ago by a goverment Grant for housing tennants free. Is this pink stuff stopping my loft breathing because it is on top of the other layer?

Mick Wilkinson, March 2009

what you need is better insulation and poly vents fitting these are none cosmetic so cheap pennies infact i have worked in the insulation industry for 26 years and have never had these fail

mike.evo@hotmail.com, February 2009

Yur problem is cause by two factors here.
1.) Not enought roof insulation laid to stop heat escape.
2.) Not enough roof ventaltion.

With the combination of the above factors this causes our good old friend CONDENSATION.
What happens is ther your warn air is slowly escaping in to your loft, and as there is little or no ventalion, this space is warming faster that it can cool.
How To Solve.
Step 1.)
Up grade you loft insulation to 225mm minimum all over, BUT be carful not to push the insulation down into the eaves to far as to let the insulation and underside of your felt come in to contact, manitain a free flow air gap of a lease the size of the timber rafters all the way round.
Step 2.)
Install sofit vents at spacing of about 800 - 1000mm apart to all side of your roof where there is a sofit. The vents can be purchased from you local diy store. Ther are white round dics of about 75mm dia
Here is and pic link.
http://www.pnpbuilders.co.uk/manage/Gallery/IMAGE_032.jpg
This WILL solve your problem.
If you need more help you can contact me here.
www.simplybuildbetter.co.uk
Thanks
Joe. D

Joe Dybowski, January 2009

To get condensation in a loft space warm, wet air must be entering the loft.

My suspicion falls on the vented bathroom and vented spin dryer - can the exhaust from these be entering the loft void? - and how good is the loft hatch?

Have you always had condensation up there in the winter or is it something recent? What might have changed to have caused it?

Peccavi, January 2009