Floating Floor Threshold and make up

[If in doubt...]

Hi, as part of ongoing garage conversion - can only squeeze in 50 - 60 mm insulation (which BC is happy with) but -

1) Is there a preferred way to support the threshold to keep it sound long term? Red section below will be main through-fare as there will be units to the left and right. I'm thinking treated timber on a bed of some kind of fixative to give a level setting on the slightly rough surface - photo makes it look a lot worse that it is. Then wrap DPM over the top to lie on the DPC - which will be reinstated between the 2 tabs shown?

2) I need to make up 78 mm so if I go 50mm insulation + preferred 22mm MR T&G Boards leaves me around 5-6 short so hardboard / plywood on top of floorboards? Or I just go 60 insulation + 18mm T&G... I've always just preferred the thicker floorboards in the past.

Cheers

 

[Wayners]

Could use a self leveler as only 5mm approx.
Then the 50mm insulation and 22mm flooring.

 

[noseall]

Hi, as part of ongoing garage conversion - can only squeeze in 50 - 60 mm insulation (which BC is happy with) but -

1) Is there a preferred way to support the threshold to keep it sound long term? Red section below will be main through-fare as there will be units to the left and right. I'm thinking treated timber on a bed of some kind of fixative to give a level setting on the slightly rough surface - photo makes it look a lot worse that it is. Then wrap DPM over the top to lie on the DPC - which will be reinstated between the 2 tabs shown?

2) I need to make up 78 mm so if I go 50mm insulation + preferred 22mm MR T&G Boards leaves me around 5-6 short so hardboard / plywood on top of floorboards? Or I just go 60 insulation + 18mm T&G... I've always just preferred the thicker floorboards in the past.

Cheers

View attachment 420719

Firstly, those bricks in the red box have to go.

By the time you have laid a bit of blinding sand, DPM and your insulation, glued floor deck, you will find it will line up perfectly.

 

[If in doubt...]

Could use a self leveler as only 5mm approx.
Then the 50mm insulation and 22mm flooring.

Thanks. The last metre and a half of the garage floor to the left in the photo does have a 15mm slope so it was in my mind to use leveller for that. I could mix up some extra - looks like it will be around 5 bags worth in total - to raise the rest of the floor, but I’ve not had a lot of experience with leveller. Just how good is it to self level that sort of area for a 3 to 5mm ?

 

[If in doubt...]

Firstly, those bricks in the red box have to go.

By the time you have laid a bit of blinding sand, DPM and your insulation, glued floor deck, you will find it will line up perfectly.

Cheers, hadn’t considered those bricks, they look pretty solid but yes they have not had any traffic over them previously.

Should I backfill with concrete seeing as it’s under the DPC?

Then re levelling - just to check, are you basing that on the sand etc making up the 78mm based on the 50mm PIR and 22mm boards? As above I do have the option of leveller but if you think the sand etc will do it that’s a nicer option.

Ta

 

[noseall]

Cheers, hadn’t considered those bricks, they look pretty solid but yes they have not had any traffic over them previously.

Should I backfill with concrete seeing as it’s under the DPC?

Then re levelling - just to check, are you basing that on the sand etc making up the 78mm based on the 50mm PIR and 22mm boards? As above I do have the option of leveller but if you think the sand etc will do it that’s a nicer option.

Ta

Yes. Do a dummy run and see where your levels sit. Use sand under the DPM to make up a few mm if necessary. You may not need any or just a smattering by the join.