{"id":1098,"date":"2013-09-04T17:20:01","date_gmt":"2013-09-04T17:20:01","guid":{"rendered":"http:\/\/idostuff.co.uk\/blogs\/?p=1098"},"modified":"2013-09-04T17:33:49","modified_gmt":"2013-09-04T17:33:49","slug":"attic-roof-insulation-and-plaster-boarding","status":"publish","type":"post","link":"https:\/\/idostuff.co.uk\/blogs\/2013\/attic-roof-insulation-and-plaster-boarding\/","title":{"rendered":"Attic Roof Insulation and Plaster Boarding"},"content":{"rendered":"

Another fiddly time sapping job to get right but WOW what a difference it makes.\u00a0 It looks like and\u00a0feels like\u00a0progress.<\/p>\n

Previously there was no insulation in at all just plaster board straight on to the rafters.\u00a0 That all got ripped out before the new roof was put on so it\u2019s been bare for a good while.<\/p>\n

Insulating the roof of the Attic Rooms<\/h2>\n

Deciding what insulation to use and how thick it needs to be is confusing with so many options available and comes under building regulations (part L 2013), Thermal Elements,\u00a0 Energy Conservation\u00a0 etc.\u00a0\u00a0 Even the manufacturers information doesn\u2019t make things much clearer for retro fitting insulation. Without going in to great detail the regulations say the U-value should be 0.18 or less.\u00a0 My research leads me to the simple answer to achieve this without taking out too much head height 115mm or more of foil faced insulation board (Kingspan, Celotex, Balytherm) is required.\u00a0<\/p>\n

For most retro fitting jobs 70mm between the rafters and 50mm under the rafters as a general guide will be sufficient to comply with building regulations.\u00a0 There are lots of factor to consider\u00a0 like rafter depth and spacing that can tweak the the U value by 0.01 or so and of course if more can be fitted it\u2019ll make up for other heat losses that can\u2019t be addressed.<\/p>\n

I chose to use 50mm between the rafters and 70mm under the rafters. This should give a U value of 0.17.<\/p>\n

\"Between<\/a>

Foil faced insulation inbetween and under roof rafters<\/p><\/div>\n

This isn\u2019t normally advised as the theory is that the outer layer (between) the rafters should be thicker than the inner layer under the rafters to prevent the \u201cpotential risk of interstitial condensation \u201c But there\u2019s many factors which can affect this in my case all in my favour.\u00a0 Please comment below if you want to know more.<\/p>\n

The cottage rafters are 3 inch. So I have fitted 50mm board between the rafters and leaving a 25mm air space to the breathable sarking membrane (if it\u2019s not breathable the ventilated gap should be 50mm). The alternative to put the 70mm board between the rafters would have been to batten out the rafters to, in effect make them deeper by 20mm.<\/p>\n

The 70mm insulation boards go under the rafters, fixed up with a few 90mm plasterboard screws. I made little washers for these from some old lino so the head didn\u2019t pull through. (Before these go up I marked where the rafters are so I know where to put the screws.)<\/p>\n

All the board are as tight a fit as practically possible. Any gaps are filled with either slivers of the board or stuffed with rockwool type insulation.\u00a0 All the joints are then sealed with aluminium tape.<\/p>\n

\"Taped<\/a>

Taped joints of foil faced insulation to make a vapour barrier<\/p><\/div>\n

Now it\u2019s looking like a proper room again and its ready for the plaster board.\u00a0 I used 12.5mm plaster board, you could use 9mm but 12.5 is a bit tougher and takes the large drywall screws better without cracking up.\u00a0 With all the angles and corners it takes some measuring and tweaking to get the largest sized boards to fit (I\u2019m using 6 x3 ft sheets) but it\u2019s worth the effort to reduce the number of joints.\u00a0<\/p>\n

note: It takes 90mm long srews to go through the insultion and get a good grip in the rafters.<\/p>\n

\"plaster<\/a>

Plaster board being fitted keeping joints to a minimum<\/p><\/div>\n

Many hours later one of the rooms was ready for a big clean up and so it was ready for the daughters to stay in.\u00a0 Thankfully the effort was appreciated.<\/p>\n","protected":false},"excerpt":{"rendered":"

Another fiddly time sapping job to get right but WOW what a difference it makes.\u00a0 It looks like and\u00a0feels like\u00a0progress. Previously there was no insulation in at all just plaster board straight on to the rafters.\u00a0 That all got ripped out before the new roof was put on so it\u2019s been bare for a good […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,5,206],"tags":[424,413,418,422,416,414,407,415,405,423,417,420,421,419],"class_list":["post-1098","post","type-post","status-publish","format-standard","hentry","category-ido-diy-stuff","category-ido-property-stuff","category-whitby-cottage","tag-424","tag-attic","tag-between","tag-building-regulations","tag-celotex","tag-foilfaced","tag-insulation","tag-kingspan","tag-loft","tag-part-l","tag-rafters","tag-thinckness","tag-u-value","tag-under"],"_links":{"self":[{"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/posts\/1098","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/comments?post=1098"}],"version-history":[{"count":4,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/posts\/1098\/revisions"}],"predecessor-version":[{"id":1103,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/posts\/1098\/revisions\/1103"}],"wp:attachment":[{"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/media?parent=1098"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/categories?post=1098"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idostuff.co.uk\/blogs\/wp-json\/wp\/v2\/tags?post=1098"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}