victorian house replacing solid floor

paulroberts

whats the correct way of making the joint between the new floor and the walls when laying a new solid floor in Victorian house?
To stop damp raising

cyclonebri1

paulroberts wrote: »

whats the correct way of making the joint between the new floor and the walls when laying a new solid floor in Victorian house?
To stop damp raising

Yes in a word, just google concrete floor construction, but basically once you've dug out to the correct depth you need to blind with sand to protect the polythene /visqueen DPC.
Lay the on the base alowing 200mm or so up each wall.
Completely layer 50mm polystyrene over the poly and also the depth of the concrete up each wall, ie, if you are laying 100m concrete floor, you need a 100mm upstand to each wall. The polythene is trimmed off just above concrete level to be covered by the skirting boards
This is to prevent cold bridging from the walls to the floor and to provide a decent level of insulation. It seems weird the 1st time you start pouring concrete on lovely soft polystyrene but it supports it and is standard practice.
You can also use extratherm or similar for better insulation still.

It comes down to if the building inspector is involved as to how much effort and insulation you put in.

Gloomendoom

You're going to need pretty thick skirting boards to cover 50mm width of polystyrene.

paulroberts

The gap between the wall and polythene DPC sometime allows moisture to be pushed into the bottom of the walls or for moisture to come up between floor and wall gap so the edge of floor will become damp how do you stop this from happening?

phil24_7

Only 50mm of polystyrene?!?! No idea what the actual building regs are but I would never use less than 100mm. 25mm insulating up-stand around the whole perimeter too as this will allow the base to expand and contract.

brightontraveller

paulroberts wrote: »

whats the correct way of making the joint between the new floor and the walls when laying a new solid floor in Victorian house?
To stop damp raising

I’d always go for a suspended timber floor as opposed concrete? former has a a variety of methods most within modest Diyers skill set? Its often cheaper, quicker, more future proof , less resource hungry, looks and feels nicer? The big disadvantage to concrete is if there is a problem rectifying can be expensive, time consuming and hard work

cyclonebri1

Gloomendoom wrote: »

You're going to need pretty thick skirting boards to cover 50mm width of polystyrene.

Don't be quite so smart, you use 25mm up the walls, but it's flush with the surface concrete level, however, is there any need to protect the last 20 mm or so up to the skirting at floor level???, NO.
Suggest you do as I advised the Op to do, google.

In any case you simply haven't got this, the insulation is at floor level and does not extend above the slab, clue up chap or don't comment, ;)

cyclonebri1

phil24_7 wrote: »

Only 50mm of polystyrene?!?! No idea what the actual building regs are but I would never use less than 100mm. 25mm insulating up-stand around the whole perimeter too as this will allow the base to expand and contract.

Then check out the actual regs, 50mm is acceptable;)

No, it forms thermal break

phil24_7

cyclonebri1 wrote: »

Then check out the actual regs, 50mm is acceptable;)

No, it forms thermal break

You would only need it on external walls for a thermal break to stop cold bridging. If you put it all the way around it performs both duties.

50mm is pathetic. You only get once chance to insulate a concrete floor so do it properly. I know many builders and none of them would settle for 50mm poly in or under a concrete floor.

Mojisola

brightontraveller wrote: »

I’d always go for a suspended timber floor as opposed concrete? former has a a variety of methods most within modest Diyers skill set? Its often cheaper, quicker, more future proof , less resource hungry, looks and feels nicer?

The big disadvantage to concrete is if there is a problem rectifying can be expensive, time consuming and hard work

We replaced the suspended floors in our house with insulated concrete and the difference in the house is really striking - much warmer and drier.

We paid for it to be done and the cost was practically the same whether we replaced the suspended floor with wood or concrete.

In my experience, the benefits far outweigh any disadvantages.

cyclonebri1

phil24_7 wrote: »

You would only need it on external walls for a thermal break to stop cold bridging. If you put it all the way around it performs both duties.

50mm is pathetic. You only get once chance to insulate a concrete floor so do it properly. I know many builders and none of them would settle for 50mm poly in or under a concrete floor.

As I said to the OP, check out the building regs, given his lack of knowledge he'll probably not put any in, I was quoting minimals that you should realise if reading my post?