Rising damp in downstairs Bathroom

[LMJ90]

Hey guys, a bit of a problem here I have in the downstairs bathroom. Rising damp on the (see pics) right side wall, and rear / outer wall. I'm thinking of getting someone in to look at it, but before I do, any ideas? House was built in 1947, and I can't see any obvious DPC under the screed (which crumbled as I took up the old quarry tiles), so it might be slate? Original copper main runs up from the floor on the left hand side. I have my suspicions of the causes.

• Front door might be leaking?
  The sewage waste pipe (into the floor) has failed / cracked / deteriorated?
  DPC failure?
  Outside waste drain cracked / failed (which is at the bottom left, outside).

The outer wall faces the prevailing wind too.
Pics (ignore the obvious damp patch on the screed (I had just put stop ends on the pipes)

Any help would be great! Thanks.

 

[dann09]

1. In 1947 a DPC would have been built into your walls - possibly some kind of bituminised arrangement.
Search and probe inside and outside for the DPC.
Are your outside ground levels lower than your FFL's?


2. The solid floor would probably not have had any kind of membrane.

3. Is the whole ground floor solid, or suspended in parts?

4. Why not post pics of the outside suspect waste/gulley(?) and wall area.

5. What layout do you intend in the bathroom? Where the pipe runs?where the fixtures?

6. Presumably you want a close coupled WC?

7. A new floor could be poured on a membrane and the walls hacked off and remedial rendered to eliminate the rising damp - if that is what it is.

8. The soil pipe can be tested for leakage. Likewise the water service.
The water service is too small in 1/2", it should be a min of 3/4"( in MDPE).

9. i dont understand the ref to "front door leaking".

 

[LMJ90]

1. In 1947 a DPC would have been built into your walls - possibly some kind of bituminised arrangement.
Search and probe inside and outside for the DPC.
Are your outside ground levels lower than your FFL's?


2. The solid floor would probably not have had any kind of membrane.

3. Is the whole ground floor solid, or suspended in parts?

4. Why not post pics of the outside suspect waste/gulley(?) and wall area.

5. What layout do you intend in the bathroom? Where the pipe runs?where the fixtures?

6. Presumably you want a close coupled WC?

7. A new floor could be poured on a membrane and the walls hacked off and remedial rendered to eliminate the rising damp - if that is what it is.

8. The soil pipe can be tested for leakage. Likewise the water service.
The water service is too small in 1/2", it should be a min of 3/4"( in MDPE).

9. i dont understand the ref to "front door leaking".

Hey Dan, thanks for the reply. I was a bit vague in areas in my post, sorry about that. I'll attach further pictures so you can paint a better picture of outside. As I've done a few jobs around the house, replacing old window sills etc, I've noticed they've used a fair amount of slate around apertures etc, so yes I'm assuming its something along the lines of slate or bitumen.

So to answer the above;

Yes, floor is approx. 7-9" above the driveway.

2. No it doesnt have a membrane. Its scattered hardcore and general earth under the solid floor.

3. No, the porch, bathroom, kitchen, hallway and under the stairs are all solid, and the rear half of the house is suspended.

4. Floor starts I'd say around the patch where the original lead bracket was;

5. I've only stripped the bathroom, someone's fitting the bathroom for us. It was just in aid of saving time, and making use of the skip we have.

6. Yes it will be close coupled.

8. I know, youre right. The pipe has since been replace all the way up from the road (MDPE) and the last stretch into the house is 22mm / 3/4".

9. We have had some issues with our UPVC front door in the past (rectified a few times, but I fear that it's still not right). The front door is in the next room (right hand side wall, on the outer wall next to the window) might be leaking in as it's rising up the other side of this bathroom wall (in the porch) too, seen below, (damp is not obvious here though);

Thanks!

 

[dann09]

1. The external render is too low, it's meeting the earth/ground. It req's cutting back a little higher. The render looks to be in a poor condition.

I suspect that the render is a factor in the damp issues. The render and the lack of a membrane.

2. The "gulley" arrangement around the soil stack appears a little odd - can you remove the cover and photo down into it?

3. The new WC soil pipe might have to come horizontal out of the wall, and tee into the soil stack. The basin waste could pick up the soil pipe outside.

4. How is the hose bib fed? Is there a tee in the MDPE branching straight up?
From external stop tap to internal stop tap should be in 3/4" MDPE.

5. Pic the exterior of the PVC door, please.

 

[LMJ90]

1. The external render is too low, it's meeting the earth/ground. It req's cutting back a little higher. The render looks to be in a poor condition.

I suspect that the render is a factor in the damp issues. The render and the lack of a membrane.

2. The "gulley" arrangement around the soil stack appears a little odd - can you remove the cover and photo down into it?

3. The new WC soil pipe might have to come horizontal out of the wall, and tee into the soil stack. The basin waste could pick up the soil pipe outside.

4. How is the hose bib fed? Is there a tee in the MDPE branching straight up?
From external stop tap to internal stop tap should be in 3/4" MDPE.

5. Pic the exterior of the PVC door, please.

I have often wondered that. How our house (in most places) could get away and remain dry with rendering all the way to the floor. As far's I know the rendering looks to be original. Though I wouldnt say its in poor condition, paint has flaked in a few places, but has been sorted. The finish looks similar to what you'd achieve using a spoon, not a float / derby lol.

Will post pics of gulley tomorrow.

Bib is teed from the MDPE just as it enters the house. New stop cock will be installed alongside the new bathroom.

PVC door has a weather strip on bottom, is there anything else you wanted to see on it?

 

[dann09]

1. the render is bridging the DPC and pulling moisture up and in by capillary action.
Same process has probably occurred with the internal plaster and the solid floor.

2. Pic the bottom detail and the whole door including it's surround.

3. Tap on the render searching for "hollowness".

 

[LMJ90]

1. the render is bridging the DPC and pulling moisture up and in by capillary action.
Same process has probably occurred with the internal plaster and the solid floor.

2. Pic the bottom detail and the whole door including it's surround.

3. Tap on the render searching for "hollowness".

True, now that I think of my mates houses / family. None have rendering coming to the floor. And yeah, I was basing my judgement on the "knocking" theory. Infact - I'm yet to come across any major blown areas. But it does make sence, as the tarmacadam outside comes right up to the rendering too.

Anyway, Since I'm keen, I've just been out to take a few additional snaps

The floor does run ever so slightly down to the right, the rubber base doesn't contact the door by the right hand corner;

Lovely!

As mentioned, the general finish of the rendering. Somewhat exaggerated by the lights!

As a side note too, see the flashing on top of the door and windows? Is that an old method of damp proofing? As I never see it on new builds, only the equiv. - which would be end/stop/bellcast beads?

Thanks again!

 

[dann09]

1. The water might be penetrating on top of the brick threshold step. Close the door, and use a spray bottle to water test the level tread and door seal, and then observe.

2. Door and window seals are often tested by blowing smoke at them - but quite how you would do that i dont know.

3. I cant see down the gulley, pic too dark.
Does the gulley have water in it? i.e. a trap?
Do you have two soil stacks? Or is one a RWP?
Does that CI pipe continue below or stop at ground level?
Is the plastic pipe, entering from the right, from the old basin? Does it simply discharge into the gulley -more pics i guess.
The render behind the gulley appears damp?

4. The lead flashings are the remains of a previous porch roof/canopy flashing. They are irrelevant.