Otter

This is amazing, thank you for this detailed response. I will read this and try and digest it all.

This is my main concern. I don't want to do all this and have to rip it all out in 12 months

I will take a look at the floor tonight and see if I have the height. I don't really need to keep the room warm as it is a gym and wont have any heating anyway. Its more about damp control. Ive been in there recently and everything was damp and the electrics had cut out because the moisture was so bad. I think it was due to a sudden change in temperature outside. There are no doors at the moment, we took them off as they are just thin wooden stable style doors where the top and bottom open independently on a gate latch. I also need to keep the sound down as we want to play music in the gym and at the moment you can hear music outside really clearly. I am hoping that with insulations and proper doors we can reduce the noise outside.

This is the room today with the delivery or plasterboard in it.

Damn, wish I had done that. The floor is down now.

Thanks for the help. So with this I can get an R value but what about moisture and air flow between the insulation. I have read that air needs to get between the insulation and the roof tiles as that it vents. I am worried that if I get this wrong then I am creating a problem that can rot the structural wood.

This is the room.

Hello all, I recently found this community and I can't wait to get stuck in. As a novice to self building I feel like at this stage I will have more questions than answer for other people but I will keep active and offer advice where I can. I have a farm with brick built stables, brick built out buildings, a barn and the main house. I am constantly working on the house when I am not at work and we hav recently passed planning to convert the stables and barn into two dwellings which we will do over time. My current project is to upgrade one of the brick storage buildings into a gym and would like advice on if I am making correct decisions. The building already has water and power, the roof has been replaced as it had no membrane and the battens had collapsed. I have taken up the floor which was made of a few hundred bricks laid on sand and replaced with mot and a concrete floor. The electrics are being upgraded to spec at the moment with a few extra sockets being added and the lights are being replaced with led. My questions is around the insulation for the walls and ceiling. My plan for the walls is to use 47mm x 47mm battens, 50mm rockwool, vapor barrier and then 12.5mm plasterboard. For the ceiling I am unsure at the moment, the rafters are 75mm deep so was thinking using 50mm of insulation block so leaving 25mm of breathing space above. Vapor barrier and then 12.5mm board. Unless I increase the depth of the rafters to add more insulation. The room is going to be used as a gym and wont be heated other than frost protection in winter. Any thoughts or advice please, I am new to this so if this is way out from regs or anything else then please let me know. Thanks Rob