Green Mould - 4 months after damp course treatment!

[kerrys2002]

I would be really very grateful for some advice...

I had a damp course/tanking treatment done in July and now I have green mould growing on the skirting board in one corner of the room. I am very concerned as I am asthmatic and I am being repeatedly told that the mould is potentially dangerous. I have contacted the company who completed the treatment (given that it's supposed to be guaranteed for 20 years) and attached pictures of the mould.

Upon reviewing the pictures, they first asked which type of skirting I had used and I explained that I had moisture resistant MDF fitted, given the damp history. They informed me that they only recommend using wood and that they outline this in their report. They claim that when you cut through the MDF, the cut through surface is not protected and so can get wet. In other words, it renders the MDF useless, but if this were the case, why do people use it?! They also claim that the screws attaching the skirting appear to have punctured the tanking and this may now require chargeable repairs. Isn’t that convenient. They fail to mention anywhere in their report that there could be a possibility that reattaching skirting could puncture the tanking. This is the first I've heard of it.

The company is coming to review the damp on Thursday. I have had nothing but aggravation from the company from the beginning and I very much regret even using them. I am concerned that they are trying to sidestep responsibility as in my opinion, the tanking has failed.

 

[AronSearle]

MDF is fine for that use, they are talking nonsense, if the damp is fixed why do you even need to use moisture resistant MDF.

Moisture resistant MDF is used for external shop facades (exposed to rain), so it's if anything overspecced for this use.

They may have you on the screws penetrating the damp course, I mean it sounds like rubbish, but it's something more tangible they can use against you.

Also no picture? and it may help to tell us why it was damp coursed in the first instance, what the wall is, what was the source of damp you were trying to eliminate?

 

[kerrys2002]

Thank you so much for your reply!

I have attached the same pictures I sent to the damp company.

I was told I was being over cautious using the moisture resistant MDF but I am a novice when it comes to all forms of DIY or building works. My purchase was for my first home that had taken me 5 years to save for so I was trying to do things right from the beginning as I can't afford to rectify any mistakes. This is why I am so concerned that the company is trying to pull a fast one.

Here is the extract from the report I given:

"The inspection revealed evidence of Rising Dampness to be affecting the areas marked in red on the attached plan (I attach a copy of the plan).

In our surveyor's opinion, this defect is due to the lack of an effective damp-proof course and also high external ground levels.

In order to remedy this defect we recommend that a new damp-proof course be installed, combined with a lateral tanking system, incorporating cementicious tanking and waterproof renderings.

[company name] damp proofing and specialist rendering systems provide a reliable, highly effective method, for the treatment of dampness and are covered by the most comprehensive guarantees available."

Obviously, that last paragraph is open to interpretation!

Please let me know if you need anything else for your evaluation and thanks again.

 

[WabbitPoo]

You MAY find that some people on here think that injected damp courses (if that is what you have) are a waste of money, and that damp companies will ALWAYS find damp....and some will claim that rising damp doesn't exist.

Bottom lie is, they guarantee no damp for x years, so its not working hence they come back and rectify it. Be prepared to have to use threat of legal action.

I am no expert, by the way. One will be along in a minute.

 

[Johnmelad]

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[AronSearle]

We need to know....

Level of the skirting boards reletive to external ground level and dpc.

Cavity wall, solid masonary?

Is the new external rendar breathable, if not, this could make the problem worse, it will not let the wall dry.

MDF is fairly dense (so less of an insulant than solid timber), and a painted surface will make it prone to condensation if it is an issue of cold spotting rather than an ingress of damp.

If you get yourself a timber moisture meter, pull of the MDF skirting, if it has a higher moisture content to the back, than the front, this would -help- to indicate if it is an issue of condensation vs damp ingress.

 

[kerrys2002]

Thank you for your reply.

You are requesting a bunch of technical information and knowledge that I just don't have. I can tell you that the surveyor found evidence of rising dampness to the affected areas marekd in red on the plan. In their opinion, the defect is due to the lack of an effective damp-proof course and also high external ground levels. This is all the information I hate.

Here is the outlined of the work completed (as per the report received from the company) and the walls are all external solid masonary walls.

- The wall plaster shall be removed from floor level up to that shown on the sketch plan (I included a picture of the plan on my response above).
- The mortar bed at the base of the wall shall be pattern drilled using a series of 10mm holes to the necessary depth.
- The wall area shall then be pressure injected using a specially formulated solution of siliconate injection fluid, until the entire depth of the wall is fully impregnated.
- The surface of the brackwork must then be tanked using a cementicious tanking system, in conjunction with pressure injected waterproof resins.
- Where a treated wall adjoins an untreated wall, a vertical damp-proof course shall be installed, by drilling vertically to the necessary height, and injecting a chemical damp proof course. The position of the vertical damp-prrof courses are shown on the sketch plan.
- The wall plaster in the areas shown will be replaced using a specialist rendering system. The premix waterproof rendering system is factory produced and consists of specially blended dried sands, cement, lime and aggregates along with polyproplyene fibres to reduce shrinkage.
- Additionally salt inhibiters and waterproofers are added, to combat the ground salts and allow replastering immediately after the damp course installation.
- Following the application of the waterproof rendering, the walls will then be skimmed with top coat plaster to provide a smooth finish.

 

[jeds]

It's unlikely you had rising damp. From the report it's obvious the external ground level is higher than the internal floor level and therefore you were definitely suffering from lateral penetrating damp. An injected dpc in this situation is useless. You were asked what the difference is in ground level from outside to inside? This isn't rocket science, could you not just estimate; half a metre, one meter, whatever? It would be useful to know. Either way a better solution would be to reduce the external level or improve the drainage to the external wall.

The wood versus mdf is a red herring. If the wall is dry it should make no difference. In any case what you see on the skirting isn't dampness, it is mould. Mould is always caused by condensation. You need reduce moisture sources and improve ventilation. That doesn't mean the skirting isn't damp though - condensation and damp are separate things but often occur in the same place.

 

[kerrys2002]

Thank you very much for your comment!

In my opinion, there would only be a difference of approxiately 8-10 inches between the external ground level from outside to inside. The house is a semi-detached Victorian house build circa 1890. The outside walls have ventilation bricks to the wall that has the mould but the bricks are open to the elements (i.e rain) and do not have any barriers or protection. You are also correct in that there isn't any appropriate drainage, in fact, no drainage at all. Which is why I am suffering from a ponding effect on the patio, and the other two walls that were treated are next to the patio.

Do you believe the surveyor should have noted all these facts and proposed an alternative solution (like the ones you mention, reducing the external level and improving the drainage) rather than just going with the 'rising dampness' and proposing the treatment offered? I feel like I've been given a dud survey for works that were also going to fail.

I have someone from the company coming to look at the mould on Thursday and I just know (given his comments regarding the MDF and the potential puncture) that they are going to try and fob me off and make me pay for additional works that I might not even need and that (given your comments), are ultimately going to fail anyway!

 

[jeds]

Pooling water next to a Victorian house is a recipe for dampness and should be sorted out. If it's only 200mm or so it shouldn't be too difficult. The top solution would be to reduce the ground level completely (to 150mm below internal ground level) and re-lay any paths or patios so they slope away from the house. Next best option is to dig out a trench along the wall - if you've got somewhere to take a drain to that's the best option, otherwise you could install a thing called a French drain.

 

[kerrys2002]

Thanks again!

My main concern is how to I negotiate with the company that I shouldn't be reliable for any chargeable repairs regarding the mould.

Do you feel I have a feasible argument that (1) the MDF issue is a non starter and (2) if the tanking has indeed been punctured by screwing on the new skirting, then why wasn't any warnings given (along with the recommendation of using wood) that the skirting should be glued and not screwed to to the wall? Why would I intentionally ruin the works that I had paid over £1600 to have done?

Also, I feel that they should mention that the treatment would only be successful if I get the additional works done that you recommend.

 

[AronSearle]

Again, I'd love to know their logic that a product designed for external use, is not suitable for an internal skirting, keep em on the backfoot on that one.

Your text seems to indicate the tanking is a chemical damp course (putting asides arguments about it being a con), how can screws penetrate a chemical damp proof course, the brick itself *becomes* the damp proof course with such treatments (that's the claim anyway).

If others are right, and I suspect so, their product simply hasn't worked.

 

[jeds]

Thanks again!

My main concern is how to I negotiate with the company that I shouldn't be reliable for any chargeable repairs regarding the mould.

Do you feel I have a feasible argument that (1) the MDF issue is a non starter and (2) if the tanking has indeed been punctured by screwing on the new skirting, then why wasn't any warnings given (along with the recommendation of using wood) that the skirting should be glued and not screwed to to the wall? Why would I intentionally ruin the works that I had paid over £1600 to have done?

Also, I feel that they should mention that the treatment would only be successful if I get the additional works done that you recommend.

What repairs are you thinking they will (can) do? The mould is not dampness, it's condensation. Probably completely unrelated to the original problem. Yes you've screwed through the tanking but the tanking probably doesn't extend much below where you've screwed anyway so the screw holes aren't going to make much difference. If I were you I'd concentrate on getting the external levels sorted. That will allow the walls to dry and balance out and they'll become slightly warmer, which might be enough to solve the mould problem. That will take several months though so in the meantime an anti mould paint will help to keep it back.

 

[AronSearle]

Jeds, wouldnt you expect it to be warmer below ground level, not colder?

 

[jeds]

Agreed but it will warm up due to being less damp. It seems the wall has been injected. The external ground level is 200mm above internal. The injection was either done from inside - which means 200mm of wall above the injection is exposed to lateral penetration. Or it was done from outside - which means the 200-250mm of wall below the injection is still exposed to lateral penetration. So either way the wall is still damp. I expect the tanking they refer to is just sand cement render with a waterproofer added. If so that is a lot colder than the lime mortar they hacked off. My advice is reduce external levels and dry the wall out. That will warm it up a bit and may be enough to resolve the condensation. Otherwise the OP will have to look at reducing moisture levels and increasing ventilation.