I am going to build a conservatory where the floor joists 150x45mm rest on plinths. There is a clay layer that is exposed in some places. There will be a ventilated space under the joists of about 150mm. I plan to insulate with polystyrene in the floor. Can I let the polystyrene lie in the joists without so-called protection from subfloor panels? Should I fill in with sand where the clay is exposed? Should I lay out plastic on the ground to prevent moisture migration? A wondering Mats.
Do not use Styrofoam or as it is actually called EPS. Mice like to build nests in it. Use XPS. If you have ventilated underneath with 150mm and that air is ventilated from the outside, I think you don't need to worry about moisture. Just make sure the posts for the conservatory are well supported by the beams in the floor.
Tip. I placed plastic spacer washers under my conservatory posts to avoid moisture migration from the floor into the posts. So-called packing washers. And attached the posts with construction screws from Essve. Also used the same screws for all beams etc. for the conservatory. Excellent.
I had dug out the organic material and filled it with macadam and a ground fabric to prevent it from growing underneath. There's also nothing that can bind moisture then.
I had chosen mineral wool instead of foam plastic, partly because it's easier to seal against the studs and the fire risk.
Do not use styrofoam or as it is actually called EPS. Mice like to build nests in such material. Use XPS. If you have it ventilated underneath with 150mm and that air is ventilated from outside, I think you don't need to worry about moisture. Just make sure that the posts for the conservatory get good support from the beams in the floor.
Tip. I placed plastic spacers under my conservatory posts to prevent moisture from creeping up from the floor into the posts. So-called packing shims And attached the posts with construction screws from Essve Also used the same screws for all beams etc. for the conservatory. Really good.
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Thanks for the advice on XPS boards. But do I need to lay baseboards at the bottom of the joists, or can the XPS boards be exposed to the ground?
Thank you for the advice about XPS boards. But do I need to lay subfloor boards at the bottom of the joist or can the XPS boards be exposed to the ground?
I have mine directly between the beams without anything underneath.
There is about 20 cm to the ground below the boards.
XPS is also called ground boards and are usually placed in the ground, such as insulation against frost around the foundation of a house.
This is how it looks where I placed my boards on the deck where there is a conservatory above.
About 10 mm between the board and the decking to avoid creaking.
See the battens they rest on. It's deck wood 28x120 that I split in half and screwed to the beams that the boards rest on.
XPS 5 cm thick bought at Byggmax. Worked great and no draft through the decking.
28x145 decking on top.
The frame for the conservatory I made from 34x145. You can see that I have angled corners on the conservatory. (Willab Garden)
Perfect for screwing the tracks for the conservatory to.
Also added a sealing strip on the underside of the tracks for the sliding sections so water doesn't go under the track and run inside.
