Dave Jones Posted June 1, 2023 Share Posted June 1, 2023 7 minutes ago, richo106 said: I won’t mention I’ve got my new shiny oak front door has a u value of 2.0🙈 things like this really highlights how much I don’t know what I’m doing 😂 I have attached a picture of my front, would the whole thing be treated as one? It has triple glazed (42mm) solar glass but the oak door is 57mm thick with only 20mm PIR in looks very smart though. Link to comment Share on other sites More sharing options...
Iceverge Posted June 1, 2023 Share Posted June 1, 2023 I don't know on the new build if the window overlaps the cavity closer. Worse case it is like this and the installers haven't done it. The cold outer leaf could be practically "touching" the inside which is a bad thermal bridge. I suspect in reality they've moved the windows more inboard and this isn't an issue. However it's still better to cover as much of the frame as practical with some insulation. However you'll need to drill a 25mm Diameter through the membrane and batten as shown in each of the four sides of the window to allow your EPS beads installer to give a quick squirt of beads to thermally isolate the windows. If you want you can drill a few extra holes in the batten only and not the membrane to visually check that it has filled to the corners (it will BTW). The Hole in the membrane can be very simply patched afterwards with a piece of A/T tape. Hey presto. A fully thermally insulated window frame. ZERO waste of insulation unlike boards products. A fully gapless install No thermal looping/bypass. Perfect A/T details. Exactly consistent frame gaps unlike other methods. A consistent pallet of very cheap materials. No need to fight with the window installers. 15 minutes ago, richo106 said: things like this really highlights how much I don’t know what I’m doing Don't worry, almost all of us are in the same boat. 1 Link to comment Share on other sites More sharing options...
Dave Jones Posted June 1, 2023 Share Posted June 1, 2023 33 minutes ago, Iceverge said: I don't know on the new build if the window overlaps the cavity closer. Worse case it is like this and the installers haven't done it. The cold outer leaf could be practically "touching" the inside which is a bad thermal bridge. I suspect in reality they've moved the windows more inboard and this isn't an issue. However it's still better to cover as much of the frame as practical with some insulation. However you'll need to drill a 25mm Diameter through the membrane and batten as shown in each of the four sides of the window to allow your EPS beads installer to give a quick squirt of beads to thermally isolate the windows. If you want you can drill a few extra holes in the batten only and not the membrane to visually check that it has filled to the corners (it will BTW). The Hole in the membrane can be very simply patched afterwards with a piece of A/T tape. Hey presto. A fully thermally insulated window frame. ZERO waste of insulation unlike boards products. A fully gapless install No thermal looping/bypass. Perfect A/T details. Exactly consistent frame gaps unlike other methods. A consistent pallet of very cheap materials. No need to fight with the window installers. Don't worry, almost all of us are in the same boat. its same in england, there is such little awareness of the new regulations amongst the trades and even the merchants. Was in Jewsons and asked when they would be stocking the thermally broken lintels as their shelfs full of the standard catnics can no longer be used. They asked what a thermally broken lintel is. I made sure at quote stage, in writing, the standard I'm expecting. For example Photo's of all the main thermal junctions have to be sent to the EPC assessor or you wont get an EPC cert on completion. Link to comment Share on other sites More sharing options...
ADLIan Posted June 1, 2023 Share Posted June 1, 2023 There is nothing in the latest Regs on thermal performance that prevents the use of standard catnic type lintels. Link to comment Share on other sites More sharing options...
Dave Jones Posted June 1, 2023 Share Posted June 1, 2023 correct, try passing sap without them. Link to comment Share on other sites More sharing options...
Iceverge Posted June 1, 2023 Share Posted June 1, 2023 Why not separate lintels? Better thermally than catnics and as cheap as chips. Precast concrete lintels for our house were about €25inc VAT per window. Link to comment Share on other sites More sharing options...
Big Jimbo Posted June 1, 2023 Share Posted June 1, 2023 19 minutes ago, Iceverge said: Why not separate lintels? Better thermally than catnics and as cheap as chips. Precast concrete lintels for our house were about €25inc VAT per window. I did think about that. I wonder what sor of U value a concrete lintel would have in relation to say a medium density block ? Link to comment Share on other sites More sharing options...
Iceverge Posted June 1, 2023 Share Posted June 1, 2023 It wouldn't matter as they would be entirely inside the heated envelope or outside of it. Link to comment Share on other sites More sharing options...
Dave Jones Posted June 2, 2023 Share Posted June 2, 2023 10 hours ago, Iceverge said: Why not separate lintels? Better thermally than catnics and as cheap as chips. Precast concrete lintels for our house were about €25inc VAT per window. they lock pants though in brickwork! Link to comment Share on other sites More sharing options...
ADLIan Posted June 2, 2023 Share Posted June 2, 2023 Lintel, concrete or other, will not affect the U value. It will affect the psi value (linear thermal bridge) which is used to assess the heat loss from this, and other, junction. Link to comment Share on other sites More sharing options...
IGP Posted June 2, 2023 Share Posted June 2, 2023 16 hours ago, Dave Jones said: Need a min of 150mm cav for EPS beads. Messy. Much prefer sheet insulation, smaller cav better U value. I’m not sure that’s true, my walls have a 65mm cavity (1930s semi) and EPS beads went in without a problem? Link to comment Share on other sites More sharing options...
Dave Jones Posted June 2, 2023 Share Posted June 2, 2023 1 hour ago, IGP said: I’m not sure that’s true, my walls have a 65mm cavity (1930s semi) and EPS beads went in without a problem? 65mm will almost certainly be a fail as well even for the lower spec refurb target. 100mm beads is a fail on new build, Link to comment Share on other sites More sharing options...
richo106 Posted July 12, 2023 Author Share Posted July 12, 2023 Hi again I am starting to do some rooms ready for plaster boarding and somehow didn’t spot this last time on majority of my upstairs windows. There is nothing in my upstairs window cavity, just open to the loft etc would it just be a case of putting PIR in there and taping it up? I have attached a pic, so any advice appreciated as always Link to comment Share on other sites More sharing options...
Iceverge Posted July 13, 2023 Share Posted July 13, 2023 I assume that you'll be insulating from above with mineral wool? If so just cut an appropriate triangular shape of mineral wool and shove it up there, careful not to block eaves ventilation if it's required. ( I've forgotten your roof Construction) . Then use airtight tape and membrane to seal the window to the wall. Then screw in J beads into the window and slot in your plasterboard. Link to comment Share on other sites More sharing options...
richo106 Posted July 14, 2023 Author Share Posted July 14, 2023 18 hours ago, Iceverge said: I assume that you'll be insulating from above with mineral wool? If so just cut an appropriate triangular shape of mineral wool and shove it up there, careful not to block eaves ventilation if it's required. ( I've forgotten your roof Construction) . Then use airtight tape and membrane to seal the window to the wall. Then screw in J beads into the window and slot in your plasterboard. That's great thank you again @Iceverge Link to comment Share on other sites More sharing options...
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