Is this rising damp?

[raok03]

Hi,

I've had this patch on the wall (its outside facing and chimney) for about 2 years. This is the worst that its been but when we got the property it just looked like condensation which is why I haven't done anything.

Its been covered by a potted plant for this duration so only noticed how bad it was in the last few days! Please note that this patch hasn't gotten any larger in size.

As the wall is external facing and the chimney has leaked in the past (leaky flashings that have since been fixed) I just wanted to get an impartial opinion before I start to get people coming in to give me a quote.

I think it might be something coming in through the walls as the it does need to be repointed and the drain is directly on the other side of that patch. I'll upload pics of the wall in the morning.

Is it worth me getting leak detection people in?

Any help is appreciated.

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• raok03
• 23 Mar 2015
• 1

 

[Joe Malone]

You won't get an impartial opinion unless you pay for it and no one can tell you what has caused the damp by looking at pictures unfortunately but as much as I can tell you is that it looks to be caused by a leak or penetrating damp.

 

[ree]

1. dont use the outlet until the damp issue has been remedied.

2. the fact that its on a chimney breast cheek might be significant.

3. you have quarry tiles so i assume that its in a kitchen with a solid floor?

4. is the wall solid or cavity?

5. the skirting is possibly rotted on the back face.

6. depending on the variables, its often a case of hacking off the affected plaster, & rendering back in lime and sand. But first, some pics?

7. Pics of the front face of the chimney breast and pics of the external area - detail pics at ground level, & whole elevation pics - would help.

8. hold off getting in any leak detection(?) people or anyone else until you've taken a little knowledge from this forum.

 

[raok03]

Hi,

Have added more pics from the outside:

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• raok03
• 24 Mar 2015
• 1

Untitled

• raok03
• 24 Mar 2015
• 1

I'll try and get more detail pics tonight.

answers to ree's questions:

1. Haven't used the socket in years.

3. It is in the kitchen but I'm not 100% that it is a solid floor. Those tiles are actually lino.

4. is the wall solid or cavity? Its a building form the 1920 so assuming there is a small cavity

Had someone come and look at it to give a quote.

Obviously they mentioned that it was rising damp due to the damp meter giving a very high reading.

But he also mentioned that given the state of the outside wall, there might be some penetration, so he suggested that it gets re-pointed along with having the drainage channel deepened.

I'm still not convinced that it is rising damp as the it has been there for 2 years and the other parts of wall are bone dry (according to the meter). Where the patch is, it looks like has been plastered over I can see where the line of the plaster has been applied and sounds hollow when I knock on it. The rest of the chimney feels solid.

The damp patch doesn't extend beyond the line of plastering (not since I moved in at least).

I'm thinking getting a damp survey done and depending on what they say,
get the leak detection people in.

Would appreciate your thoughts.

 

[ree]

9. measure the thickness of the wall please. You might have a solid wall given that a few headers are in view?
and also determine the floor type if you will?

10. Hack out to 20mm to 25mm and re-point in lime and sand.

11. where is your DPC on the external pics?

12. Is any splash coming down from the gutter/roof area?

13. The external ground level has been raised over the years. The existing channel was probably cut to provide a remedial measure against the damp.
Could be that a new channel, a French drain, should be installed.

14. carefully examine the whole of that wall at low level in the kitchen and beyond, esp. the other cheek of the chimney breast.

 

[raok03]

Just found the original building survey, answers below:

9. Its solid wall, approx 255mm thick. Floors is softwood floorboard suspended on joists etc.

10. I'm guessing you're suggesting this as remedial action so will get a quote for that.

11. Survey mentioned couldn't see dpc, but most likely would be slate (if there ever was one)

12. Gutters have been replaced and this morning it was raining (not heavy, so it was dry near the wall - you can just about see that in one of the pics). However, the drain does overflow in very heavy rain - I guess I should get this cleared out.

13. The other guy mentioned this too, so will get a quote for this also.

14. The rest of the wall seems to be free of damp, as mentioned the meter readings were clear. Other side of the chimney is behind units so can't check.

Ree, thanks for all of your help - I really appreciate it.

 

[ree]

9. Its highly likely that moisture is penetrating the wall.

9A. given that its a suspended floor then you possibly have an earth filled hearth in front of the c/breast. The hearth will be trimmed with joists. - google pics of this, or search on here.

9B. No pics yet of the c/breast but the flue(s) should be swept and top & bottom flue ventilation provided.

9C. the underfloor joisting should be checked for fungal decay - you will have to get under and crawl.
No air bricks are shown in the pics? Do you have sufficient air bricks for a good underfloor thro ventilation?

11. Probe the mortar beds with a screwdriver to search for a DPC.

12. "the drain" - do you mean the gulley?

14. Built in units on a damp external wall are trouble waiting or happening. Perhaps remove a unit back near the c/breast and maybe pull an appliance - to examine the wall. Pics would help?

So, you might have damp because of moisture penetration, from the hearth or from the sulpherisation in the sooty flue?

 

[seasickstevie]

... the drain does overflow in very heavy rain - I guess I should get this cleared out.

Top of the 'suspicion' list.

 

[raok03]

9B. There are ventilation holes on the chimney breast, both in the kitchen and the room above. They're open all the time.

9C. There is a large grill under the door on the entrance to the garden. The survey said it would provide sufficient air flow

11. I'm not overly technical - if its a slate DPC how will I know what it looks like. I don't want to damage anything!

12. Yes the little gully between the wall and the brick paving is what was mentioned to be lowered. The guttering the the pictures flow into a drain that is pretty much directly on the other side where the damp patch is showing.

14. Will try to pics.

Thanks again for your help on this.

I'm planning on getting the outside re-pointed (just the first few layers of brick) and the gully deepened along the length of the wall and the drain cleared.

I'll also get the patch sorted out or should I wait until the other works are completed?

 

[ree]

9A. you dont mention researching 9A - its important.

9B. all your flues should be opened and swept - you will possibly find one or two of them to be rubble filled - the upstairs flue is not connected to the kitchen flue. All flues vent one fireplace only.

9C. air bricks should be on approx 2m centres.

11. just probe - you will know when you've hit a DPC of any material. No damage will be done.

12. For the time being, i was leaving out advising you on the gulley the drain and the RWP arrangements. Where does that gulley drain to - a manhole or a sump?

15. DIY remove the skirtings in the affected area and knock off the affected plaster - 300mm beyond any damp signs - back to brick. Cut the paint/caulk before prising the skirtings free. Then pic and post the result.

Isolate the outlet before any work.

 

[raok03]

9A. Hi, not sure what to research. Googled 'hearth timmed with joists' and lots of pics I don't really understand

9B. Seeing as I'm thinking of getting the chimneys removed completely, should I just do that? Should reveal what problems lie behind. Don't really want to get the chimney opened up just to fill it back up.

9C. Just a rather large grille under the door. No air bricks along the wall at all.

12. Believe it goes into the main drainage out the house. Will try to dig up plans from survey.

15. Someone else has mentioned this too. Will do this over the weekend and post some pics. The other guy said to hack out all the plaster down to the brick and then monitor the bricks for damp.

Thanks again

 

[ree]

9A. and 9B. and 15.

The earth filled hearth could be causing rising damp issues esp. below the back hearth in the fire opening. The trimming timbers could also be at risk of fungal infection.

However, if you are intending to remove the chimney breast from the kitchen then there is no need to deal with the hearth or flue issues yet. There's actually no need to do any interior work if the c/breast is soon to go - it can all be done then.
Advice could be given ref. removing the c/breast but dont confuse the issues until you have resolved on exactly what you are going to do.

FWIW: "All flues vent one fireplace only" actually means a separate flue for each fire opening.

 

[raok03]

Thanks - I'll expose the brick behind the patch anyway for now to try and see what's happening. If it looks bad then the decision to remove the chimney will have been made for me.

I'll go ahead with the exterior work in terms of pointing and getting that gully deepened

Thanks for all your advice on this.

 

[jeds]

Around a chimney breast there are several possible sources of moisture and you also have a drain and downpipe there as well which give even more possible sources. Plus it could also be simple rising damp - although I doubt it. So you've got to narrow it down. The plaster is well contaminated anyway and will probably have to come off eventually so my advice is remove the skirting and hack it off now, 150mm or so beyond the stain. Check the position and type of dpc and if there is excessive moisture above or below. That will at least tell you if you are dealing with moisture from below or above.

 

[regsmyth]

My guess would be the drain too.
Do you know where it drains to?
Use a hosepipe and see how quickly it backs up and overflows.
If it's not draining properly you need to sort it out.