ninja432

OK thanks. I'm still wondering what to do about the sill. The original sill is exactly the same width as the frame. Is this ok to have it like this? I'm noticing all the windows come with a sill that is wider than the frame.

Ok I will get a sill for sure. PeterW, nice ideas but purely to keep things simple and so I don't have to bother cladding on the outside, Ill just get the custom made windows. I am noticing that the windows I'm looking at come with a sill 100mm wider than the frame. My original window has a sill exactly the same width as the frame. Is this bad? I was thinking Ill just get them to make the sill the same width as the frame?

Great thanks. Seems quite straightforward. So no cementing necessary then? Am now trying to think of a reason why I need a window sill. I am converting the garage inside. A stud wall and a wooden frame will be made to surround the window. The original has a sill outside but surely it doesn't matter if I just buy the window with out a sill and fit it?

Can I get some advice on the procedure for fitting a new window in the single brick wall of my garage? I am going to get a brand new double glazed unit. The old original timber one is approx 106x188cm, seems to be not a common size, so I think I'll need a custom made unit. It appears to just be secured with screws and bit of mortar so shouldn't be too difficult to remove.

I am hanging the joists from the walls. With a 50mm ventilation gap underneath. DPM on top of the joists. I don't fully understand your last question "between existing floor level and the existing garage floor" Do you mean between the existing floor level and the new floor? if so, I'm probably going for 100mm deep joists (also supported from underneath) and insulation. Then 22mm flooring.

Ok, these plans with the screed on top of the insulation or the concrete first and then insulate and board are all sounding good. However I haven't worked with cement much and don't trust my abilities to get it level. I have worked with timber and that's where I feel confident. So it's the Hanging joists with support plan for me. My conundrum now is how to support the insulation between the joists. With only a 50mm ventilation cavity underneath, applying a Vapour Permeable Breather Membrane, underneath the insulation, sounds a bit tricky. So maybe using insulation netting is the way to go.

When you say quality of floor, do you mean how level it is? it looks a little bumpy in places.

Quick question about the joists, if I need to use packers underneath, will the plastic type do the job, or do I need something like steel or roofing slate?

Ok so I have had a good think about all my options and I think I'm going to hang the joists from the wall and allow an air cavity underneath as well as between the outer and inner wall. So I'm wondering how big the cavity should be, minimum? I don't have a lot of height in this garage so don't want to go too high. Also with the joists, I was going to use 45x95mm's, spaced 600mm apart and they will be about 4.2M long. Will they need any support, aside from the hangers at each end?

Ok gotcha, thanks!

What, so are there are 3 types of membrane then? When you say "vapour membrane", do you mean this then: https://www.jewson.co.uk/building-materials/drainage/foundation-materials/damp-proof-membrane/products/FNPYF003/visqueen-damp-proof-membrane-blue-4m-x-25m/ ??

Ok so when you say vapour membrane, do you mean this stuff: https://www.jewson.co.uk/building-materials/thermal-insulation/condensation-control/products/FNPF0510/proctor-breather-membrane-beigec2a050g-100m-x-1000mm/ this is different to DPM right? Why does the guy in this video put the vapour membrane on the other side of the insulation, to where you say it needs to be? Is he doing it wrong? I am noticing different people have different opinions on where these layers need to be.

Ok I have looked up what screed is. Well my drawing board is currently being constructed via this forum, phone calls to a a family member who is a professional builder (albeit one who is difficult to contact at times) and also drawing from experience I have working on a renovation project a few years back. I am converting the garage to a studio, not living space and in this instance planning permission is not required.

The block wall is a single skin. What is a vapour membrane? Ok so if I support the joists above the floor, would I do this with blocks? And what about the insulation, if the joists are supported above the floor, then the insulation would fall through? What is Screed?

Ok JS Harris, thanks, I didn't realise I had the DPM placement incorrect. And what about leaving a gap somewhere between one of these layers, is that necessary? Russel Griffiths, yes, a concrete floor that I am putting joists onto. I didn't even know you could get liquid DPM, thanks, I will look into that.