How to remove & remedy a failed chemical DPC

[drpepe]

Hi - any help would be appreciated...

Terraced house c1901 (central property of 3), which we moved into nearly 3 years ago - our house was originally the left hand side of a pair of semis, with the now adjoining left hand house built some years after ours (c1930s). This adjoining house is approximately 30cm higher than ours (based on comparing doorstep levels). This might be important as it would place their party wall dpc above ours.

I have posted several posts in the past about the lack of underfloor ventilation & high humidity which have been partially dealt with (extra airbricks and clearing out rubble from the underfloor), but the current problem is not directly related to this. The left hand party wall has fairly recently (4-5 years) had a chemical DPC and been replastered to ~1.2m along the party wall in the front hallway. However horizontal damp stains are appearing all along at 1.2m height (see pic for an example).

View media item 96337
I presume that the chemical DPC has failed or never actually worked, and that what I can see is rising damp being forced out of the wall above the re-plastered 1.2m?

What would be the remedy for this ? Presuming I can't do anything about next door, do I need to allow this wall to breathe or go in the opposite direction and think about tanking?

Any suggestions greatly appreciated!

 

[ree]

Is the wall in the pic a cavity wall?

Is the pic showing below the stairs?

Does the damp run the length of the party wall - behind kitchen units for example?

Please, more pics of the damp showing the floor, and pics of where the two houses join at ground level?

 

[JohnD]

you don't need to remove and remedy the useless chemical treatment. You need to find the fault that is delivering water to the fabric of your house, and fix it.

Do you know where the incoming water pipes are in your house, and the one next door? They might go in a straight line, between where the kitchen used to be when the house was built, and where the stopcock by the garden gate used to be. Have the pipes been replaced already? They probably started leaking long before they were 100 years old.

Have you and the neighbour got water meters?

 

[footprints]

Did you have it done professionally? If so many firms give a long guarantee 25 years or so, worth a call to them first.

 

[cAtLeYx]

As your property is c1901 we can safely assume there is no cavity wall. The difference between floor levels between your property and your neighbours has no bearing on the location of the DPC / slate. It could lower or equally higher, either of which you can't change. John D has a valid point that the incoming water supply which may still even be a lead pipe, could be leaking and be the source of water. On the basis that you moved into the property a few years after the works were carried out we are not sure if you even know who carried out the works. As footprints said most chemical treatments come with a lengthy guarantee. On the basis that you clearly need to carryout "opening up works" to remedy / further investgate this problem anyway, why not remove the skirting, a few floorboard and post what see below.

 

[stuart45]

As your property is c1901 we can safely assume there is no cavity wall.

It does depend on which part of the country you live in. On the South Coast in places like Hampshire there are many houses with cavity walls built from around 1860 onwards.

 

[cAtLeYx]

But these are not true cavity's as we have now. The two individual leafs would have been tied together using the stone work and therefore can attribute to bridging between the two skins.

 

[ree]

cAtLeYx,

1. No, you cant: "safely assume there is no cavity wall" - houses from the 1875 Public Health Act were being built with cavities, and some from even earlier. The kind of knowledge that someone who claims to be a "senior construction manager" should know?
I think that all "we" can "safely assume" is that your technical claims are a bit Walter Mitty.

2. The 1930's house to the left is an add on, and could have been built with a separate "party wall" ie. two flank walls forming a separated "party wall"(some were, i've demolished them) - read the OP's post, its in simple English.

3. There's no need to capitalise or underline for emphasis - typically, only graduates from Walter Mitty University do that kind of semi-literate stuff.

4. "The difference between floor levels has no bearing on the location of the DPC" - are you being serious? "it could be higher or lower" - than what? How about there possibly being two DPC's ?

5. i doubt that a 1930's house had a slate DPC?

6. There's no lead water pipe - read the OP's post, and so much more information is implied if you have the technical knowledge to read what is being provided.

7. No fresh "opening up works" (sic) are needed. Keep staring at the OP's post, and keep attempting to think whats implied?

8. "post what see below" - dont take it personal, but a pronoun is missing. Perhaps your "degree in construction" didn't cover pronouns?

9. just noticed your latest confusion: dont start wriggling about whats a true cavity and whats not. You said that: "we can safely assume there is no cavity wall" sic.
You are claiming a single wall. Or does your command of simple English fail again? Or is simple thinking your problem?
We have no indication of how the OP's party walls were built - but AAMOI, my technically limited friend, tie-in stones were not a common feature of 1930's building practice.

10. Just noticed your further confusion in not knowing the difference between a DPC and a DPM.

Where exactly did you graduate from?

 

[stuart45]

But these are not true cavity's as we have now.

The ones I worked on in Portsmouth were. 2 skins of brick, 3 inch cavity and iron ties. The stone ones in Bristol like my daughter lived in are solid walls.

 

[JohnD]

I watched the demolition of a bigg-ish detached house on the Essex/London fringes, built about 1890, which had a cavity construction with an outer 9" wall and an inner half-brick wall, with iron ties. It looked like it had been expensive when built, I think shortly after a station had been built nearby with access to the City.

 

[stuart45]

Some builders around that time used a 9 inch wall on either the outer or inner skin. It was possibly that they didn't have the confidence in 2 skins of 4 inch compared to the solid walls they had been used to building.

 

[cAtLeYx]

Thanks Again Ree - you seem to make provocative posts on many occasions perhaps its the only way you can type more than one sentence without asking a million and one questions, that sometimes have no bearing on the origin question.

I shall address your points one at a time.

1. Yes my statement regarding the cavity was generalising.
2. Yes agreed the party wall could have any manner of constructions. - I fail to see how re-reading the post has any bearing on my ability to read English - There is no evidence there.
3. Pointless comment.
4. Yes perfectly serious. Both properties could have the DPC at the same height with one property having its floor joist higher.
5. You doubt or know for a fact - We can only speculate. hence why i used DPC / slate.
6. Where does it state the water pipe has or has not been replaced
7. Pointless comment.
8. Pointless comment.
9. See 1 above
10. There was no confusion - was a simple typo.

Happy to continue.

 

[stuart45]

What would be the remedy for this ? Presuming I can't do anything about next door, do I need to allow this wall to breathe or go in the opposite direction and think about tanking?

Any suggestions greatly appreciated!

Years ago i would have said tanking, but now I would think about replacing with lime render and plaster. 10 years ago there were half a dozen firms round here doing lime work, but now there are loads of them. I've done lime work in my own place and it has been much better.

 

[ree]

Your opening remarks - give me an example of where i ask questions that: "have no bearing on the origin (sic) question?


1. No it wasn't it was definitive, note the word "safely". Stop wriggling - is this how you make your : "senior construction manager" decisions? You didn't know what you were talking about. The OP actually used the term: "their party wall".

2. Not at all, not in the OP's case - we were given enough information about the two houses to make an informed surmise about any possible cavity.
You didn't understand what you were reading - previous you were pretty certain, now its: "any manner of construction" - this after the OP has referred to: "their party wall" & its implications of a cavity.

Either you cant read whats on the page or you simply dont understand what you read - which is it please?

3. If its "pointless" then why do you keep doing it?

4. Agreed, i now understand your point. You were right. I was wrong. I apologise.

5. "You doubt (sic) or know for a fact" - I dont even "know for a fact" if it has a DPC either, neither do you but you are happy to argue about it because its the kind of common assumption thats usually held when talking about a 1930's house.

6. If you had read intelligently, and gathered all the facts before giving an opinion, you would have noticed that the OP mentioned: "several previous posts". I'd suggest that you read them and examine the previous pics, and then come back here.

7. Far from pointless - just read the OP's "previous posts" and have a think about what has already been revealed?
Is the method in: "senior construction management" these days to discard unfavorable evidence? Way to go.

8. "and therefore can attribute (sic) bridging between the two skins." You have a curious way with the English language - one would expect a "construction graduate" who holds a "senior management position" to do little better.

9. Another wriggle - so you dont actually or specifically mean what you say? As in: We senior construction managers typically use generalisations when we dont know what we are talking about?

10. Well just how many of these "typo's" do you usually allow yourself - i think the quota is up for this thread, dont you?

 

[cAtLeYx]

Ree -

Your opening remarks - give me an example of where i ask questions that: "have no bearing on the origin (sic) question?

I do not need to search too far, you have asked within this thread "is the pic showing below the stairs" - Where is the relevance.?

2. Not at all, not in the OP's case - we were given enough information about the two houses to make an informed surmise about any possible cavity.

Then why did you ask "Is the wall in the pic a cavity wall?"

3. If its "pointless" then why do you keep doing it?

We are here to offer our advise on construction, not literacy.

4. Agreed, i now understand your point. You were right. I was wrong. I apologise.

Thank You

5. "You doubt (sic) or know for a fact" - I dont even "know for a fact" if it has a DPC either, neither do you but you are happy to argue about it because its the kind of common assumption thats usually held when talking about a 1930's house.

Then why did you respond to my original post with "i doubt that a 1930's house had a slate DPC?" if you don't know either?

6. If you had read intelligently, and gathered all the facts before giving an opinion, you would have noticed that the OP mentioned: "several previous posts". I'd suggest that you read them and examine the previous pics, and then come back here.

My reply was purely based on the information offered in the tread, as you are fully aware I am new to the forum and unlike you have not had the benefit on responded the the original posters previous treads,

"and therefore can attribute (sic) bridging between the two skins." You have a curious way with the English language - one would expect a "construction graduate" who holds a "senior management position" to do little better.

This response from you has no bearing what so ever on my knowledge of construction.

Another wriggle - so you dont actually or specifically mean what you say? As in: We senior construction managers typically use generalisations when we dont know what we are talking about?

I think you will find that you generalised in a previous post just this weekend.
You wrote - From what i can see i dont think that you have lintels above any of the frames in the pics. Which would be unusual for a 1970's build? - No its not unusual there were thousand of houses constructed in the 70,s that relied on the windows sub-frame and bed reinforcement above.

Read more: //www.diynot.com/diy/threads/h...lintel-above-the-window.445283/#ixzz3qJtc3pTy

10. Well just how many of these "typo's" do you usually allow yourself - i think the quota is up for this thread, dont you?

As many Typo's as I like.

I do also find is fascinating how you have chosen to single my post out for commenting against. For example.

Do you know where the incoming water pipes are in your house, and the one next door? They might go in a straight line, between where the kitchen used to be when the house was built, and where the stopcock by the garden gate used to be. Have the pipes been replaced already? They probably started leaking long before they were 100 years old.

I did not see comment from you pointing him in the direction of previous posts or reading deeper into the post.

Perhaps you could be a professional and let me know why you feel the overwhelming urge to comment on mine.