Condensation in loft. 11 December 2022 at 5:03PM in In my home (includes DIY) MoneySaving 87 replies 6.4K views

SergeantBaker

Just been into my loft to collect the Christmas decorations, a couple of the plastic boxes had some water on the top so I've clearly got an issue with mine too. I can however feel a draft throughout the loft. 

stuart45

Most people only go into the loft before Christmas, and if it's mild there is less chance of condensation. This year is a lot colder than normal, so there will be a lot more wetter roof spaces.

Slinky

We had a trip to the loft yesterday, condensation having been spotted a couple of weeks ago by one of the builders. This is on the north side of the house. We had work done on the bathroom, the ceiling was reskimmed and the lights were left dangling, so I suspect that will have given an easy route for heat to escape. Lights now pushed back in place. We've also had a new boiler and hot water tank, the plumber hasn't filled any of the holes in the airing cupboard loft where he removed pipes, so we need to sort that out. We've shoved a thick duvet in the top cupboard hopefully cutting the airflow a bit.

The one thing we did find, was that where the electricians had been putting new extractors and lights in the bathrooms, they'd pulled the insulation out of the way and not put it back. In some places there was next to nothing, in others, a pile 2.5 feet high! We've sorted this out spreading it back where it should be, but be aware if trades have been in your loft, don't assume they've left your insulation how they found it.

womble12345

I have noticed a similar issue when going in my loft recently, sounds like a load of us are going to buy these lap vents. Where is the best place people have found to buy them? They do seem quite expensive for what they are so I cannot help but think there is a cheaper supplier out there somewhere.

littleboo

I got two boxes of 10 fom Amazon in Jan, installed all but one and they definitely created a noticeable airflow. I haven't been up in the recent cold spell but was getting condensation on the north side last winter, so will take a look later. 

ashe

littleboo said:

I got two boxes of 10 fom Amazon in Jan, installed all but one and they definitely created a noticeable airflow. I haven't been up in the recent cold spell but was getting condensation on the north side last winter, so will take a look later. 

Be good to know!

womble12345 said:

I have noticed a similar issue when going in my loft recently, sounds like a load of us are going to buy these lap vents. Where is the best place people have found to buy them? They do seem quite expensive for what they are so I cannot help but think there is a cheaper supplier out there somewhere.

I got 10 from Amazon for £25 delivered but I reckon I'll need at least 10 more. They are out of stock now but there are some sellers on ebay 

im taking the nuclear option. I'm getting our roofer to install 3 soffit/fascia vents on each side of the house, i'm going to install probably 20 lap vents and I'm going to install a PIV to help with in-house condensation which will hopefully help draw in air to the loft also

I've ordered 22 spotlights hoods and some silicone sealant to cover those up and finally I will top up our insulation with extra 200mm 

I think from all the posts I've found on forums and Facebook it's this felt we all have that is to blame as it is not breathable. Every picture I come address looks the same and many people in the roofing trade are saying it's nonbreathable and seems to be a common issue currently - hopefully by getting as much airflow into the loft as possible I can stop the condensation or at least massively reduce it 

badatDIY

I have the same - as others have said think it's the especially cold weather at least in part.

I am going to draught proof my loft hatch this weekend, and also install some of those felt lap vents and ensure insulation is pulled away from the eaves. If none of that works I guess I might be contracting a roofer or builder to add some more serious ventilation. Handily I am end of terrace so presumably they could just core a vent or two through the gable end wall from the inside rather than having to faff around with scaffolding and tiles.

As for the lap vents - its marginally cheaper to buy them direct from Ashbrook Roofing (who seem to be the people selling them on both ebay and amazon anyway!) but not by that much. They do seem expensive for what they literally are, but ultimately if they work they are far cheaper than rotten timber in your roof!

ashe

badatDIY said:

I have the same - as others have said think it's the especially cold weather at least in part.

I am going to draught proof my loft hatch this weekend, and also install some of those felt lap vents and ensure insulation is pulled away from the eaves. If none of that works I guess I might be contracting a roofer or builder to add some more serious ventilation. Handily I am end of terrace so presumably they could just core a vent or two through the gable end wall from the inside rather than having to faff around with scaffolding and tiles.

As for the lap vents - its marginally cheaper to buy them direct from Ashbrook Roofing (who seem to be the people selling them on both ebay and amazon anyway!) but not by that much. They do seem expensive for what they literally are, but ultimately if they work they are far cheaper than rotten timber in your roof!

Thanks for the tip; yes cheaper from them but seemingly out of stock which is convenient if they're the ones selling them elsewhere! 

superstylin

In the spirit of money saving, do we think short lengths of pipe lagging could do the same job? Wedged between felt to keep it separated - I imagine you could stick a cut in the top to allow it slot onto the felt to stop it falling through. 

marycanary

At last, I've found one benefit of having an old roof with torching most of which has fallen out onto the insulation.