J.A.S.'s fixing the damp & swimming pool in the house thread....

John_Pierpoint

It sounds just like the sub floor of my son's "new" house built circa 1930 - though his is a dry as a bone.

Being able to get at the underside of the property is useful - we have discovered that the house is on its third set of electrical wiring and second central heating system, not to mention the "shrine" to the Spice Girls from the 1990s.

As you seem to seem to be built on a former "pond" there might be no scope for sending the water down hill in a land drain or underground into a deep soak-away, though digging/boring a hole should reveal the winter time natural level of the water table and possibly reveal that someone in the past has "puddled" the clay to deliberately collect rainwater.
http://www.e-lindsey.gov.uk/NR/rdonlyres/CAB4A83D-2850-4026-B29E-0D25685D96AA/0/046Surfacewatersoakaway.pdf
http://en.wikipedia.org/wiki/Puddling_%28engineering%29
Technically speaking dumping "surface" water into the sewer is illegal as is now building an extension and running the rain water down the drive and into the road gutters - what the eye does not see the heart does not grieve.

Existing buildings will be paying a modest surcharge on their sewage bill for disposal of rainwater.
(those knowing that all their rainwater goes to soakaways would be well advised to check to see if they are paying this surcharge).

Once you have got a drained "basement" and effective damp course to your building, the walls might dry out completely; though, after generations of rising damp ineffectively treated, there may be deliquescent salts at a high concentration trapped in the wall.
I would not rush into plastering an "impermeable" layer onto the wall and thus forcing the rising damp ever further up the wall.

JustAnotherSaver

I read that rising damp will only go 'so high' (about 1.5m i'm sure i read), but i don't know if this is a myth or not & rising damp may shoot 100mtr high if it so wishes. Some of the stuff i've read will be true, some of it wont, question is which-is-which.

I've also been reading a bit about these soakaways lately & having rain water absorb in to the ground as opposed to having it out into a drain. I understand the logic behind it but i can't help but feel that this is not an all round foolproof idea. The ground, certainly in really bad rain would surely become absolutely sodden?? Which will be up against the house which 1) can't be good for it and 2) with my underfloor already bad enough as it is will be even worse.
At least if it's in a drain that's it, ta ta bye bye (so long as the drain isn't leaking).

There must be a tool that makes it easier to bore into the ground to determine the water table? I can't imagine 1 man & his shovel on a weekend being set to task. It'd take all day & make an incredible mess. Besides, we only have a very small patch of grass out the back corner & about a cars size patch at the front of the house. Eventually it'll only be the patch at the rear that'll remain.

"shrine" to the Spice Girls from the 1990s.

Had to laugh at this one

Once you have got a drained "basement"

I can't help but feel the sub floor will perhaps never be drained properly. We've at least another 2 professionals to bring in yet so we'll see what they say, but if they sing from the same hymn sheet as yesterdays chap then it's not a good idea to solid floor the entire thing & interrupt the flow of water (i say 'flow' but who knows. It may not be coming from front to back or side to side, it may be coming up from below for all i know).

there may be deliquescent salts at a high concentration trapped in the wall.
I would not rush into plastering an "impermeable" layer onto the wall and thus forcing the rising damp ever further up the wall.

I had a re-read through the damp mans recommendations on a re-plaster & he was quite specific with the plaster to be used & the anti sulphate wash & all that malarkey so the wall could still breathe.

Anyway, as ever once the professional has gone, you then think of questions that you should've asked but that escaped you. Yesterday was certainly no exception...

Currently we have a 'hatch' opening to the subfloor, cut into the floorboards. If we go concrete beams & blocks then....

1) How do we get into the sub floor? (would we even need to?)
2) What about if the sub floor fills up real bad/high?
3) Would we still have a sump pump fitted in such a set up? If yes, then again we refer back to question #1.


Just have to wait now. I know of one guy i'm going to try & get to come & look when he's back at work. Just need another at least.

cyclonebri1

John_Pierpoint wrote: »

If there really is a water course running under the house, then I agree you don't want to block it and the concrete joist man is making a good point.
If the walls are so badly "corroded" by two or three generations of rising damp, that a silicon injection is not enough , using modern diamond cutting techniques, it should be possible to insert a real damp course, while the floors are up.and the joists being replaced.

How much is the gap between the bottom of the joists and the concrete (?) floor of your "basement" ?

What did you find on the old maps for the "field" that used to be the site of your house?

if you find a black line with this written alongside it

---

> Drain you know that old boys toiled with wooden shovels to try to clear a water-logging problem.

I did 1 of these back in the 70's simply with a lump hammer and about a ton of lead sheet:rotfl::rotfl::rotfl:. Yep, funny but true.


JAS, if the water level comes up that high you won't need to worry, you will need sandbags to stop it coming in through the door.:A

JustAnotherSaver

Ask & ye shall receive....

I measured up today & took down the readings as it was asked what they were....

* From the floor (subfloor) to the start of the joist in a direct vertical line .... 820mm
* From the floor to the top of the joist ... 1010mm
* From the floor to the top of the floorboards ... 1040mm

I know that not all of those were asked but i thought i'd get a few various readings. It also shows how guesswork is pointless as my 5ft guess was miles out :rotfl:


Though i forgot to measure the length of the joists. I was trying to price up concrete beams last night & the longest i found was 4500mm.
The current wooden joists run from front to rear of house. Going off the EA brochure:

Through Lounge
22'4" (into bay) x 10'10" (6.8m (into bay) x 3.3m).

6800mm is quite a length & i wonder 1) whether beams would stretch that long or whether they'd be supported somehow in the middle of the room 2) whether they would flip the beams so they run from side to side instead. Problem though then is that it's then into the party wall, so i suspect this would be a no-no. Again, another question i forgot to ask.

John_Pierpoint

There is almost certainly a honeycomb wall (or two) down there ? that could be used to support the shorter joists ends at mid span - if not you could probably build one without too much palaver.

JustAnotherSaver

Yeah i did think that that's the approach they'd possibly go. Just wondered still.

There is a wall there in the middle. It's not really thick IIRC so they'd probably have to adapt/modify/rebuild for it to take some proper weight.

We've been told to track the depth of the water. It's raining a bit today so was back to 4.5".
The thing with if going beam & block is that nothing will remove that water. Once there, the only thing removing it is the pump, but it (at this time of year at least) is regularly 4.5" high. That's a lot of moist air that will continue to be there bridging the DPC.

Anyway i look forward to getting in chap 2 & 3 to see what they reckon up. The flooring situation is almost by-the-by, it's what you do about that water, what level you 'accept' etc that i'm interested in what they come up with.

cyclonebri1

JustAnotherSaver wrote: »

Yeah i did think that that's the approach they'd possibly go. Just wondered still.

There is a wall there in the middle. It's not really thick IIRC so they'd probably have to adapt/modify/rebuild for it to take some proper weight.

We've been told to track the depth of the water. It's raining a bit today so was back to 4.5".
The thing with if going beam & block is that nothing will remove that water. Once there, the only thing removing it is the pump, but it (at this time of year at least) is regularly 4.5" high. That's a lot of moist air that will continue to be there bridging the DPC.

Anyway i look forward to getting in chap 2 & 3 to see what they reckon up. The flooring situation is almost by-the-by, it's what you do about that water, what level you 'accept' etc that i'm interested in what they come up with.

That's the issue I have with this, plus, and I'm not sure you have this fully understood, the amount of wet down there will be causing penetration of moisture to above. Ok, less of a problem with concrete joints if the insulation and screeding is up to scratch, but I'd sooner not have the subfloor laking up.

And don't forget it is very difficult to put an access hatch in a beam and block floor.

John_Pierpoint

you could knock access through the external brick wall big enough to crawl inside; if building in a manhole cover really is impossible, though I cannot see why it should be.

cyclonebri1

John_Pierpoint wrote: »

you could knock access through the external brick wall big enough to crawl inside; if building in a manhole cover really is impossible, though I cannot see why it should be.

But John, would any builder take the trouble to do this, plus it would break the vapour barrier unless sealed very carefully.

Outside access?, would need a pit, and that will create it's own "well".

Sorry, not crying you down, just trying to find a practical route, ;)

JustAnotherSaver

cyclonebri1 wrote: »

but I'd sooner not have the subfloor laking up.

And i totally agree.

I've spoken to more builders today. I don't particularly like the ones i saw today, so i wouldn't have them doing the job, but it doesn't stop me asking them.

So far everyone is of a mind that the wet floor should be left :mad: The other concern/point that was raised is how do you get the floor dry enough to do any work. Within 2 hours the float is at 90 degrees & within 7 hours the level is back to 4.5 inch. It simply doesn't stay dry anywhere near long enough.

I spoke with my manager today too. I know he knows a bit about the building game although i'm not sure how much. He said he'd go for the solid floor approach with a double DPC layer. I can't remember the order he said he'd go in, so let's say for arguments sake it was hardcore, DPC sheeting, concrete, DPC, insulation, screed. I've no idea of the order so that'll probably sound funny to you, but the point is he said double DPC to try & better stop the damp/wet.

But he's not seen it yet.

The chap i want to come out & have a look wont be back until Monday though. Just need to select another guy in the meantime.