Flooring question

MouldyOldDough

We are looking at an extension to provide a larger kitchen and downstairs toilet - these would be on the rear side of the house, to double the kitchen size (or more)

The present house has suspended floors , with an airbrick in the wall in the middle of where the extension will go - the extension, presumably will have solid floors - how do you link the two - do you have ducts through the concrete floors ?

Or would they rip up the kitchen floor and fill it with concrete ? Whatever they do - at some point, there must be an interface between the two types of floor.

stuart45

If you want a concrete slab floor in the extension, then a duct through the floor is required.

MouldyOldDough

stuart45 said:

If you want a concrete slab floor in the extension, then a duct through the floor is needed.

I am only assuming that a solid floor will be used - we are only at the pre-planning stage

I thought that suspended floors were no longer used ?

stuart45

Suspended floors are still used. They can be either concrete block and beam or timber. Concrete floors are often preferred for kitchens and bathrooms.

grumbler

Beam and block with crawling space underneath would be my only choice, especially for a kitchen.

ThisIsWeird

I wouldn't 'worry' about such details, but you are doing the right thing by considering them for when discussions actually begin. I certainly don't see them ripping up a perfectly good existing floor for no good reason, just to make it match the new - that would be nuts. ('Good' reasons could be if they found rot in your existing, or if you were to UFH the whole area, old and new.)

Keeping ventilation going to the existing underfloor isn't a problem - they just lay ducts in the new solid floor to the new outside wall.

The recommendation/decision for the new floor type - discussed with Architect and Builder - will likely be based on floor height above ground; is it quicker and easier to fill in, lay a slab, insulate and screed, or to suspend? I let my builder decide this, and he went 'solid'.

Other factors could be; are you having UFH? Will the change in floor 'feel' bother you if they are different (there was a thread on here not too long ago about someone who couldn't cope with the change in floor type. I go from suspended timber to solid - doesn't bother me a jot).

MouldyOldDough

ThisIsWeird said:

I wouldn't 'worry' about such details, but you are doing the right thing by considering them for when discussions actually begin. I certainly don't see them ripping up a perfectly good existing floor for no good reason, just to make it match the new - that would be nuts. ('Good' reasons could be if they found rot in your existing, or if you were to UFH the whole area, old and new.)

Keeping ventilation going to the existing underfloor isn't a problem - they just lay ducts in the new solid floor to the new outside wall.

The recommendation/decision for the new floor type - discussed with Architect and Builder - will likely be based on floor height above ground; is it quicker and easier to fill in, lay a slab, insulate and screed, or to suspend? I let my builder decide this, and he went 'solid'.

Other factors could be; are you having UFH? Will the change in floor 'feel' bother you if they are different (there was a thread on here not too long ago about someone who couldn't cope with the change in floor type. I go from suspended timber to solid - doesn't bother me a jot).

That's the problem - there is a 2 1/2 ft difference between the floor height at the rear of the house compared to the front

It is built on a slope !

UFH - Too expensive

stuart45

Which part is the highest, front or back?

MouldyOldDough

stuart45 said:

Which part is the highest, front or back?

Front - we have a 3 foot drop (steps) to exit the conservatory

stuart45

It sounds like the rear extension will need a suspended floor. As a general rule of thumb, 600m fill is around the maximum depth of fill recommended for a ground bearing slab. They can be suspended by sitting the slab on the inner skin with rebar, or more commonly block and beam.