Kenbob007

@MikeGrahamT21 not me, I'm afraid...

@Redbeard, thank you 🙏

Hi @Redbeard....what if I change the DPM for aluminium foil Membrane? I really don't need to buy much for what I need and I can get the ally in a much smaller roll....

Top work Redbeard. Appreciate you taking the time to reply in such detail. It really helps me, thanks 👍

Hi! Thanks for your reply. Yes, I am in England. Being the skeiling I don't have that sort of space to play with. The rafters are only 100mm deep so only 50mm PIR can fit between them (50mm air gap above PIR). That would mean a minimum of 75mm PIR would need to go below the rafters bringing the line of the ceiling below the window reveal. The rest of the flat ceiling is covered with around 250mm of loft insulation....does it that help me in terms of regs?

Thanks for your reply. Glad to hear I'm on the right lines. Any thoughts on the VCL and butyl tape? 25mm with the 12.5mm p/board on top as much as I can lose really. 50mm would come very close to the top of the the window reveal and look odd imo. The reason I'm leaving the plastering to a pro is that room in particular has a horrible textured paint ceiling (not artex) so I'm going to get the pro to skim the entire ceiling flat as well as the skeiling....but will probably tape and fill in advance to keep cost down. The house was thrown together quickly after WWII. In having an full width extension to the rear a few years, the builder found all sorts of interesting construction techniques hidden inside the walls 🤣

Hi! First time poster here... I have noticed of late that condensation and mould is forming on the inside face of the plastered skeilings in each of our upstairs room. Went into the loft the other day and found that there no insulation at all behind the skeilings! I have researched this loads over the last few days but thought it would be best to run my plan and some questions past those who know better In one of the rooms, the skeiling is peppered with cracks as well as the mould/condensation so I plan to start there. Here is the sequence I'm looking at... 1. Pull away existing loft insulation and clean up dirt inside the loft around the skeiling. 2. Remove existing plasterboard. 3. Fit roofing battens to side of rafters, set 50mm back (100mm rafters). 4. Cut and friction fit 50mm PIR insulation between rafters (leaving 50mm air gap to roof membrane), angle the bottom edge to sit flat on top of wall plate (low expansion expanding foam to fill any gaps with wall plate) and oversail top edge past plasterboard on ceiling (possibly easier said than done), foil tape to joints between PIR and rafters. 5. Cut and screws 25mm PIR insulation to rafters running across the skeiling, underneath the rafters and 50mm PIR, angle top and bottom edges to fit tight to existing wall and ceiling (low expansion expanding foam to fill any gaps), foil tape to joints in PIR. 6. Cut and staple vapour control layer to 25mm PIR, foil tape to all edges to seal it against the PIR 7. Cut and screw standard plasterboard to rafters through VCL and PIR, angle top and bottom edges to fit tight to existing wall and ceiling using low expansion expanding foam to fill any gaps 8. Get a professional plasterer to do a better job than me of plastering the skeiling!! Is this a sound plan? Have I missed anything out? And can anyone help me with these questions? Q1: is this 25mm PIR totally necessary? Q2: is the VCL necessary and can anyone recommend what type to go for? Q3: should I use double sided butyl tape on the face of the 25mm PIR in line with the rafters to avoid any holes in the VCL? Looking forward to hearing people's view on this...cheers