IMM wrote:

"The Natural Philosopher" wrote in message
...

Chris wrote:


The Natural Philosopher wrote in message

...

Chris wrote:



I'm considering concrete beam and block to replace a suspended timber
ground floor. Can anyone give an idea of the cost comparison for
concrete and timber. I'm only looking at a room size of about 4m x 5m.
Thanks, Chris.

If DIY probably cheaper. Contact travis perkins for a quote.
You need to get the beams made specially to size.

However its usually cheaper to just chuck hardcore and cement down and
then DPM and screed. Any reason for suspended? BCO insisted in my case
due to large areas/wet clay/presence of tree roots etc.

The void below the floor is greater than 600mm which would make
infilling a problem. This is an old solid walled terrace house so I'm
also wondering how the not inconsiderable self-weight of the floor
will be supported.

Probably by adding some pillars, or a wall inside the wall etc.

The beams need to be well supported.

600mm on a smallish floor area is not much to infill - a few tons of
crushed limestone whacked down, and over filled with concrete..


Where does the insulation go?


Between the top screed dressing (3-4") and the concrete. Over a DPM.

Th eidea is to provide a stable sub base of crushed material that won';t
wash away or encourage tree roots in neasr teh surface, then a fairly
structural layer of concrete, possibly reinforced, then a damp and heat
isulatiuon lateyer, then a surcfae finsih of not partiucularly strong
material (screed) to provide smoothness.

If you look at the building regs, you will find that such a floor has a
far lower U value than its dimensions and the insulatin suggest: This is
because the sub base and earth itself provide significant insulation in
themselves, being very massive.

I think we calculated last year that a 3 meter thinck stone wall would
also meet building regulatins for insulation values as well. Those old
castles weren't cold and draughty after all.