Advice on remedial works to a cold garage conversion

D13exile

Hi

The 23 year old house I recently bought has a converted garage that's used as a children's playroom. However the temperature in there is always five to six degrees lower than the rest of the house as I've measured it with a thermometer. You really feel the temperature drop when you walk into it as the rest of the house is very warm and well insulated. I'm in the process of refurbishing it and I've discovered that this was converted "on the cheap". The walls have the bare minimum of glass fibre as "insulation" under the plasterboard, the floor is planks on top of joists over a 6 inch void with a vent to the outside, and while I haven't poked my head into the roofspace (as there's no access hatch), I'm guessing that there's little or no insulation up there.

My plan is to do the following:
1. Cut an access hatch into the roofspace and insulate it to the maximum, while allowing the roof space to breathe

2. I can't afford to get concrete poured and a dpc laid on a new floor so I'll be sticking with the existing floor layout. However I plan to lay a polythene barrier on top of the floorboards (to eliminate droughts up into the room) and then put down insulation under a new laminate floor. The existing vent will allow any moisture under the floor to escape to the outside.

3. As the room is only 2.4 meters wide, I don't want to dry line it as I don't want to lose anymore width off the room. I would doubt that there is a space to pump in insulation as I fear the walls are blocks laid on the flat. So external insulation would be my only bet but that would decrease the size of the side passage as the house is a semi detached.

Any tips or advice or comment on this?

BryanF

2. Lift floor boards, insulate between joists and lay membrane over top - taped & sealed. Ensure sub floor vents are open.

What’s the width of the side access? Surely you can loose 6’’?

drunkmonkey

Can you take off old wall slabs and put in some good insulated ones.

BryanF

Block Walls should be plastered first.

Calahonda52

https://www.nsai.ie/S-R-54-2014-Code-of-Practice.aspx

Is it an A roof/lean-to roof
are u sure the ceiling is not a concrete slab?

D13exile

Thanks for the advice. The ceiling is plasterboard with a roofspace above as I took an old shower out of the utility at the back of the garage conversion and I poked a hole in the ceiling and put my phone up through the hole and took a snapshot. What I could see was minimal insulation (an inch or two) between the joists. As for the side entrance, it's barely three feet wide and losing 6 inches off it would make it very tight for wheelie bins to fit down the passage.

If I had the money, I'd probably demolish it and start again but the budget is limited to minor remedial works to try eliminate heat loss through the ceiling and floor.

BryanF

Wheel bin is 600mm. If you don’t want to lose 80 inside that’s the option, assuming you go below paths and wrap insulation at eaves.