Hello
Am about to start the inside of my extension and am just looking for some advice and tips and some one to run an expert eye over my plan.
The extension is a directly onto the back of the house with a standard lean to roof (pitch 16 degrees) containing 3 velux windows. Wall construction is 9" cavity block.
The plan is as follows:
1. Insulate between the rafters with 4" Thermoboard, allowing 2" of ventiiation space between the breathable membrane and the insulation.
2. Put in the 1.5mm twin and earth cable for the ceiling lights and switches (installing approx 12 spotlights)
3. Slab the ceiling with 9.5mm plasterboard butt jointed together and drill out for the spotlights
4. Batten out the walls and insulate between with 2" Thermoboard,
5. Install the 2.5mm twin and earth cable and socket boxes etc on the walls.
6. Put a vapour membrane outside this and slab with 12.5mm plasterboard.
7. Scrim tape the 12.5mm boards together, and tape the external and internal corners of the walls with corner tape.
8. Get a plasterer to hardwall the ceiling and walls. Thin coat angle beads to be used around all corners and around the velux windows. ( My skills do not extend to the art form of plastering)
As I think over this I have a couple of questions.
1. Should there be a vapour barrier between the bottom of the rafters and the 9.5mm plasterboard ?
2. Regarding vapour barriers, Is standard polythene sheeting ok or should I be using a breathable membrane. I have some breathable membrane left over from the roof so could I use this ??
3. Staying on the ceiling piece should I drill out for the spot lights before or after I get the plasterer to skim.
4. What depth of hardwall should I be looking to get applied to the ceilings and the walls.
5. Do the tapered joints on the walls need to be filled level before hardwalling or can it all be done by the plasterer in one go ?
6 Are there any considerations I need to take into account regarding the velux windows ?
Appreciate and help and advice.
Thanks
Am about to start the inside of my extension and am just looking for some advice and tips and some one to run an expert eye over my plan.
The extension is a directly onto the back of the house with a standard lean to roof (pitch 16 degrees) containing 3 velux windows. Wall construction is 9" cavity block.
The plan is as follows:
1. Insulate between the rafters with 4" Thermoboard, allowing 2" of ventiiation space between the breathable membrane and the insulation.
2. Put in the 1.5mm twin and earth cable for the ceiling lights and switches (installing approx 12 spotlights)
3. Slab the ceiling with 9.5mm plasterboard butt jointed together and drill out for the spotlights
4. Batten out the walls and insulate between with 2" Thermoboard,
5. Install the 2.5mm twin and earth cable and socket boxes etc on the walls.
6. Put a vapour membrane outside this and slab with 12.5mm plasterboard.
7. Scrim tape the 12.5mm boards together, and tape the external and internal corners of the walls with corner tape.
8. Get a plasterer to hardwall the ceiling and walls. Thin coat angle beads to be used around all corners and around the velux windows. ( My skills do not extend to the art form of plastering)
As I think over this I have a couple of questions.
1. Should there be a vapour barrier between the bottom of the rafters and the 9.5mm plasterboard ?
2. Regarding vapour barriers, Is standard polythene sheeting ok or should I be using a breathable membrane. I have some breathable membrane left over from the roof so could I use this ??
3. Staying on the ceiling piece should I drill out for the spot lights before or after I get the plasterer to skim.
4. What depth of hardwall should I be looking to get applied to the ceilings and the walls.
5. Do the tapered joints on the walls need to be filled level before hardwalling or can it all be done by the plasterer in one go ?
6 Are there any considerations I need to take into account regarding the velux windows ?
Appreciate and help and advice.
Thanks
