MortarThePoint Posted November 23, 2020 Posted November 23, 2020 What approaches have people used before to close the cavity at the top before blown beads are installed?
PeterW Posted November 23, 2020 Posted November 23, 2020 Where I could we used folded over cavity batt as we had a pack on site but didn’t bother with gables etc as the cement board closed them off. Got a few million beads blowing around the soffits too ... 1
MortarThePoint Posted November 23, 2020 Author Posted November 23, 2020 I had wondered if DPC would be Andy good. It would stop air flow which may or may not be a good thing
OnlyAlan Posted November 24, 2020 Posted November 24, 2020 My situation was like PeterW's above but I didn't inspect the internal course ascarefully as I might have. The result was a pile of beads of more than a cubic metre in my loft. Ah well, it adds to the loft insulation.
tonyshouse Posted November 24, 2020 Posted November 24, 2020 How will the wall insulation join with the roof/loft insulation?
MortarThePoint Posted November 25, 2020 Author Posted November 25, 2020 21 hours ago, tonyshouse said: How will the wall insulation join with the roof/loft insulation? The loft insulation will come down to the top of the beads, but I was planning to do that afterwards
Oz07 Posted November 25, 2020 Posted November 25, 2020 Better off with cavity batts. They're firmer, less susceptible to moisture, easier to work with and would have better insulation properties for the given thickness
Mr Punter Posted November 25, 2020 Posted November 25, 2020 1 hour ago, Oz07 said: Better off with cavity batts. They're firmer, less susceptible to moisture, easier to work with and would have better insulation properties for the given thickness The eps beads go down to 0.032 lambda which is the same as the best fibre batts. There is also little risk of gaps or missing pieces. I am not sure about price though. Someone @Brickie? mentioned that with a wide cavity it is easier to use batts as they support the wall ties which otherwise lose their balance and there may therefore be a temptation to just push the ties into the joints.
Mr Punter Posted November 25, 2020 Posted November 25, 2020 Just now, Oz07 said: I meant to block off top cavity @Mr Punter Do you favour beads or batts for the rest of the wall?
Oz07 Posted November 25, 2020 Posted November 25, 2020 Think I'd favour beads if I could get them at a reasonable price. Always used batts or blown in fibre up to now. Where i am is forgiving weather wise though. They have been using the beads on a job I've been on recently think they need to up the glue ratio it has been snowing whenever a hole is made.
Oz07 Posted November 25, 2020 Posted November 25, 2020 Also I would favour batts if ever having to form a tray at dpc level. It doesn't take much dropped compo to bridge a cavity. Horses for courses.
Dave Jones Posted November 25, 2020 Posted November 25, 2020 use cavity closers before the wall plate goes on.
Mr Punter Posted November 25, 2020 Posted November 25, 2020 41 minutes ago, Oz07 said: Also I would favour batts if ever having to form a tray at dpc level. It doesn't take much dropped compo to bridge a cavity. Horses for courses. Leave some bricks out at the bottom and rake it clean? Not sure how practical this is though. On my current project we the upper floors are built off a wide steel plate so will need a cavity tray at the bottom.
Oz07 Posted November 25, 2020 Posted November 25, 2020 You do see it often on sites bricks left out for this reason. For me it would give more reason just to use batts
tonyshouse Posted November 26, 2020 Posted November 26, 2020 Nice, for me the op has too little insulation in the eaves zone and almost none over the wall plate ?
Iceverge Posted November 26, 2020 Posted November 26, 2020 7 hours ago, tonyshouse said: Nice, for me the op has too little insulation in the eaves zone and almost none over the wall plate ? As a workaround adding extra insulation below the roof joists or a fillet piece internally might work if aiming for low thermal bridging at the eaves.
MortarThePoint Posted November 26, 2020 Author Posted November 26, 2020 This is part of the construction drawing. The loft insulation is to overlap the wall plate and cavity insulation.
MortarThePoint Posted November 26, 2020 Author Posted November 26, 2020 On 25/11/2020 at 11:11, Oz07 said: What's that rippled black plastic called? I presume it's to create a ventilation gap between insulation and roofing membrane
Mr Punter Posted November 26, 2020 Posted November 26, 2020 10 minutes ago, MortarThePoint said: What's that rippled black plastic called? I presume it's to create a ventilation gap between insulation and roofing membrane Roll out rafter tray
Oz07 Posted November 27, 2020 Posted November 27, 2020 Egg box sh!t. As in " get me another roll of that egg box sh!t"
PeterW Posted November 27, 2020 Posted November 27, 2020 8 hours ago, MortarThePoint said: What's that rippled black plastic called? I presume it's to create a ventilation gap between insulation and roofing membrane Only required if you don’t use breather membrane as airflow is not required otherwise.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now