ROOFING EAVES DETAIL

[MikeG.]

It had to be ripped out of a few NT properties at huge expense. Without fact checking first, I understand that the company went bust overnight and opened the following day under a slightly altered name. I'm not a fan of such behaviour, and as such, I won't specify lambswool. Further, lambswool is no better in any way than mineral wool ("fibreglass"), the new versions of which are very user friendly unlike the old yellow then pink stuff, and mineral wool is almost exclusively made of recycled materials. Sometimes, the familiar standard stuff is a better bet than the new kid on the block.

 

[rhrwilliams]

I do not agree. The problem is mineral wool etc is simply not as good as sleeps / lambs wool in terms of breathability and when moisture management is important. The stuff made from recycled glass etc will not absorb moisture and thus is not as acceptable in highly breathable construction types - e.g typically on the extreme end of the scale very old timber frames etc and on the lesser end of that scale older masonry properties. Humidity and humidity levels can be regulated better with sheep's wool and hemp etc and is the reason why NT / Historic England use it on their properties which are usually also subject to long term humidity testing.

Historic Scotland also did a very good study a while ago where they tested different insulation's. SPAB and Historic England have also just done a new report which is not released yet but is draft format and looks at breathable insulation's in different scenarios.

That all said....I do agree that closing a company and starting back up again is not really cricket !

 

[MikeG.]

If hygroscopic qualities are the main priority then Warmcell 500, made from recycled newsprint, is a good place to start for those not committed to lambswool. Thing is, I treat controlled ventilation as a priority, so internal humidity issues aren't ever an issue needing mitigating.

 

[whiskywill]

I am insulating with Sheep's Wool

Are you aware of the potential moth problem? http://www.telegraph.co.uk/news/2017/09 ... gue-moths/

 

[rhrwilliams]

I think the moth problem was confined to a batches supplied by thermafleece circa 2012. Other suppliers were not effected and its been used quite extensively since the bad batches without repeat problems. Ive used it on quite a few projects since say 2014 and never had a problem with it.

https://ntenvironmentalwork.net/2011/05 ... nsulation/

 

[rhrwilliams]

Lol I'm going to get Moths now after saying that !

 

[Woody2Shoes]

Lol I'm going to get Moths now after saying that !

I've never used lambswool, but personally I wouldn't risk it. I imagine that the insecticide chemicals it must be treated with are pretty fierce, which reduces its eco-friendly credentials. Have you looked at the metallised foil type insulation (another potentially controversial option, I guess)?

From your mockup picture, I guess you're not planning to use/make/buy eaves tiles. Edit: just seen one on looking at the pic again!

Cheers, W2S

 

[rhrwilliams]

To be honest I don't think its a big risk. Despite one bad batch from one manufacturer (not the others who have been producing it for donkeys years) there have not been other issues.

I think its treated with Borax. I don't really use it because its enviro friendly as such - Ive seen lots of damage to old buildings from the wrong insulation and materials (intersistual condensation / misunderstanding of moisture in old buildings) and generally foil backed stuff and anything that won't absorb moisture is not ideal in an old house. That said, if the person installing / designing it has a full understanding of how it will behave etc there is no reason why it could not be used.