Pack 20 Roofing Felt Lap Vent Stops Loft roof Condensation/Attic Space Ventilation Airflow

My house has suffered for several years with a condensation problem in the loft, due to bituminous felt and inadequate ventilation as built. I have used condensation absorbers with limited results, and the price of these has crept steadily upwards in recent years. For under £50, the kit of 20 of these vents seemed worth trying. I installed them in February when we were going through a few cold snaps, and within a couple of weeks the slightly musty smell had gone, never to return, and the dripping of condensation on the loft timbers and flooring has completely disappeared. OK, so the loft is a bit colder, but I don't live up there, and it might be a bit cooler in the summer. I can thoroughly recommend these lap vents to anyone experiencing similar problems. They are a doddle to fit, but to get the best through-flow of ventilation, some need to be installed at low level over the eaves, and for a guy in his late-60s that was a bit of an ask, but well worth the effort. Excellent product.

I have had issues with very bad condensation in the loft for a couple years now, I’ve had roofers quote me in excess of £1k to fix (roof vents etc), additionally, my loft is partially boarded which supposedly alters the airflow. I saw these mentioned on a forum and thought it was worth a go.Delivered quickly and they are pretty straight forward to fit. The instructions say you should try to get most of them as close to the eves as possible, also under the batons if possible to maximise airflow. I decided on ordering 20, one between each beam on both sides, with every other being as low as possible. Then staggering the ones at different heights in-between.I could notice the difference in airflow almost immediately and this pretty much cured the condensation in most of the attic, but highlighted that the seal on my hatch has failed. This is because some condensation remained, but only directly above the hatch, nowhere else. After replacing that seal my attic is now completely dry, even during this recent cold snap, where before it would’ve been absolutely soaking up there.I can without a doubt say that these do as advertised and increase the airflow in your loft, but there may be other underlying issues that may also need to be addressed in order to fully cure any condensation. Overall I am very happy I have managed to solve this condensation issue for a fraction of what I was quoted by professionals.

We live in a 4 bed detached house and suddenly started having trouble with condensation in the loft - it was pretty bad with drips coming off the felt. Rather than mucking about with getting soffit vents fitted I thought I’d give these a whirl.I read other reviews that said that you’d probably need more than 10 so I thought I’d start with 20 and see how it went.I tried shoving them in randomly between the overlaps in the roofing felt and often found that either tiles or wood batons were obstructing the vent from being fitted. The result was that the placement wasn’t quite as random as I’d have hoped (which is said to improve air flow).However, the end result is good. We don’t seem to have any evidence of condensation any more! That said, it has been a bit warmer these last few weeks so only time will tell.A little expensive for what they are (considering they’re just injection moulded plastic) and one of them broke a little during insertion. Others have said that sticking some halved pipe insulation between the felt would work just as well but these were convenient and pretty easy to install - aside from the issues I had with the exact structure of my roof.

Hadn't been in the loft for a couple of months so was really surprised at my findings when I did go up a couple of weeks ago. The ceiling was totalky drenched with water droplets (condensation), there was damp on the floor, insulation and rafters. A couple of rafters were showing signs of mold growth, everything felt damp and some boxes actually had puddles of water on them (no exaggeration). Immediately did some research and ordered these items. Cleaned out mold fully, tidied up loft and installed these about two weeks ago, and despite having lots of reservations, these things worked a treat. Loft is now completely free from any condensation ... even signs of the mold had disappeared, so genuinely surprised and could not believe it. Installation was very simple. The loft is now obviously colder due to the outside air coming in, but better this than condensation. Early days but time will tell if it does deliver long term. Main downside is price which seems very expensive for what is essentially very basic flimsy PVC. I guess you're paying for the design, ease of use and primarily the niche product/market.

Like many people I have had my loft boarded which alters the airflow. For the last few years I have had severe problems with condensation which I tried to fix with leaving the loft hatch open and covering everything with polythene. I read somewhere that these are vital if you have had your loft boarded and they are!Easy to fit between the joins in the felt, took no time at all and now the loft has good ventilation and no signs of condensation.

I've got a fairly small loft space which was always running with condensation and soaking anything that was stored in there and turning the roof joists black. I'd never heard of these and somebody recommended them to me so I bought 20 and fitted 10 each side, slipping them between the roofing felt as described. Within a few days condensation on the roofing felt had gone and now a few weeks later everything inside the loft is bone dry. Absolute lifesavers as I thought I was going to have to pay a roofer a fortune to fit vents but these are a godsend!

A simple DIY install in the loft felt on the roof.It definitely increased airflow, as I was suffering from bad condensation last winter to the point of it dripping down.The condensation lessened but can't see it completely cured it - I'll be watching this winter to see how it goes.But for the cost and ease of setup, definitely worth a go.