Chimney removed and hearth screeded to floor level

[JP_]

Is this ok? I questioned it with my builder, who said damp course in place and latexed over.

But surely damp could penetrate from the wall, if it got damp? And, now not possible to insulate that bit below. Is this ok? More concerned about damp than cold, but a big cold spot could get damp in winter...

 

[bobasd]

you will possbly/probly get damp coming up through the old hearth an fireplace.
it should have all been dug out to below hearth trimming plate level, about400mm - 500mmdeep from FFL.
and a patch of suspended floor thrown across.
replace all damage 5" t an g floor boards.
whoever took that smashed board out didnt now what they were doin.
and all hearth trimming joists checked for rot and that ther is DPC strips under the joists an any plates.


ive no idea what damp course in place an latexed over means?thers no signs of a membrane bei in place under the new work? an no injection holes in the back wall?

youve gotto wire brush the soot off the back wal and render with sand an lime not gypsum.
whats happening above? is the upper chimney breast still there or is it gone.
ifits still ther hows it supported?
are the walls insulated or Dot an Dab?

 

[JP_]

That's a solid wall and the plan is to insulate with kingspan with pinkgrip foam.

The floorboard was eaten by woodworm by the looks of things, others seem ok but I'll take them out and put new in after treating all woof down there. Really it's just that hearth I'm worried about. Although, why does the wall need to be wire brushed?

 

[blup]

It looks as if the top few inches of the hearth were removed and screeded over, after application of a liquid dpc (if that is what meant by latexing). If so, it is not clear what, if anything, has been achieved in terms of preventing the return of damp as a liquid dpc would not be retained by the broken up base of the original hearth, and likewise the vertical edges.

Can you post pics of the hearth from under the floor on the left side?

Blup

 

[bobasd]

thers a few questions not answered?

woodworm is atracted to damp or unventilated areas.
the board was smashed out - you dont smash out you cut an carefuly remove.

soot penetrates most everything, remove it an render.

 

[JP_]

Board was not smashed out, it collapsed when I stood on it!
Me being me, after the first bit collapsed, I tested all the bits around with my foot too.
I'll be improving ventilation with better and maybe additional air bricks, and clearing out all the crap that has accumulated down there.
Woodworm seems to be very localised though, other boards seem OK. Will take out that corner and replace though.
Will probably lift most floorboards so I can:

clean it out
check (replace if need be) and treat joists
move electric sockets
insulate.

 

[JP_]

not sure what this shows.... some pics from below.

 

[blup]

Looks like the screed has percolated through the expanding foam.

First time I've seen expanding foam used as a damp proofing material but others may differ.

Blup

 

[bobasd]

take it all out from the hearth areas an dig out as above said.what youve got ther is amateur hour stuff thats goin to come back an bite you in the future.
is ther vegetation growing near the rotted wood below the floor?

 

[JP_]

Don't think there's any vegetation

 

[blup]

If there is no effective barrier to damp from the wall, and the floor, the new hearth will be affected as will the joists and timbers around it.

Digging out the hearth is relatively straightforward for a diyer but bridging the joists over the resulting void is a little more challenging.

Best to get in another builder or even have a survey done as it is difficult to judge accurately from pictures alone.

Blup

 

[JP_]

Have removed someb boards. Screed looks thin. Guess it needs to go down to dwarf wall height fit wall plate them new joist over. Will get them back to do this as they are coming back anyway for other work.

 

[bobasd]

before liftin any more boards dig the hearth out as above.

the rusted cut nail in the photo shos damp is present.check your other nail heads surroundin the hearth.
or even check around the whole floor. rusted nail heads are a quick sign that damp is present below a suspended floor.
where did the broken bits of particle board come from?

you dont have a knee wall around the hearth its a fender wall.
whats the plate you propose tofit?

still some questions id be intersted in?

 

[JP_]

Still lifting floorboards, riddled with woodworm, will probably replace alll

Bits of particle board from wall.

By plate meant 2x4 on dwarf wall, which joist sits on.

New pic....

 

[JP_]

New pic

Floorboards now have few bore holes, joist along hearth looks good.