DPC Keeps Failing

[pg1984]

Hi,
I am hoping somebody will be able to help me. I was a naive first time buyer and bought a ground floor flat about nine years ago which I knew had damp issues but I thought they would be easy to fix. I called out Kenwood and proten for quotes and ended up going with proten and got a course of DPC done on an external wall with a 20 year guarantee in 2014.

After four years I noticed salts and called them back and they redid the wall but instead of 1.2 m they replastered around 50 cm , four years later it looks like it has failed again as i can see salts, please look at pictures attached I'm not sure why it keeps on failing? Or whether DPC was the answer in the first place.

I am having sleepless nights worried about what it could be and why it keeps failing and am feeling a bit in despair at the damage as i cannot afford to keep redecorating etc and i now have tenants in there and am worried that they may leave...

@PigletJohn thank you so much. I really appreciate all your kind thoughts.

Just to clarify these are the points I am going to discuss with the builder:

• iron pipe next to door step leaking. check if cracked in ground
• check for signs of cracked or sunken ground or paving?
• check down the manhole
• check for raised ground level
• check if clay pipe and bend are cracked in the ground? Need to excavate

Do you think a builder can to cover the above points or do you think i need an independent damp surveyor (CRST/CSSW) qualified?

Thank you again so grateful

@PigletJohn

Thank you so much for your invaluable insights

So just confirming, I will get the builder to focus on:

• the leaking iron pipe
• check the manholes
• check for raised ground levels
• excavate down to the clay pipe and check where cracked etc

Do you think a builder is ok to do this or should it be an independent surveyor (CRST/CSSW) qualified?

Thank you so much again , so so grateful

(just as an aside- I spent yesterday chiselling ill-advised tanking plaster off a wall under a bay window. Behind it, in areas where the original lime plaster was plastered over, the lime was dry, but the wallpaper on top of the tanked plaster was cold and slightly damp. Oddly enough, the lime plaster, when exposed, felt not just drier, but warmer to the touch than the (rubbish) tanking. In this instance, the tanking had not only failed to solve whatever problem there originally may have been (most probably just condensation, or leaks from old salt-glazed drains which turned out to have cracks round there, they're now replaced by plastic) but had created a problem in itself- plus it had been applied on top of wallpaper in some areas, an offence for which the person doing it should, IMHO, have all their fingernails pulled out. Though it did mean some of the tanking came off in large pieces, as of course it hadn't stuck to the plaster behind the paper..... The tide mark of damp on the wallpaper backing corresponded neatly with the tanking plaster. We're having it replastered with lime. )

A good builder can do all that.

Have you spoken to previous clients and looked at their work?

@PigletJohn thank you so much for your reply. I haven't seen any of their work at all, I've got the number of the builder from a residence Association WhatsApp group that I joined and asked for a builders recommendation. I did ask last night if people had used him themselves and any feedback on him and around six people also have come back saying he is trustworthy, reliable and affordable so I am assuming that is good enough I guess although I have not seen his work myself...

Worth a look. They will often be pleased to show you.

You wouldn't want to find that the six recommendations are all from his mum and brothers.

OP, did you get a chance to open the manhole yet? A picture of the inside would be great.

@PigletJohn

Thanks so much.

On a seperate note , the kitchen - i have never had problems with mould at all in the 9 years that i have owned the flat, but the last 2 years, around winter time i think i have seen mould by the wall down by the floor and by the top of window near the ceiling on the wall (both external walls). I have no radiator or humidstat/extractor fan in the wall, i only have an extractor hood above the cooking hob which i dont know if its any good or even extracts properly.

What would you suggest in this instance? Could the builder do anything for this? thank you again.

Mould and damp near the ceiling of a kitchen or bathroom is probably condensation from rising steam.

Near the floor might be building damp, especially if it is a concrete floor and an old house. Waterpipes commonly leak after about 50 years.

If your cooker is on an external wall you can look outside to see if the hood extracts through a vent. If not you can add one.

@PigletJohn thank you for your reply.

If it is rising steam, what can be done to counteract condensation damp?

Thanks so much

A powerful extractor fan, that works and is used consistently to remove the water vapour. In some cases, more insulation above the ceiling will keep it warmer so less prone to condensation.

Uninsulated solid external walls are particularly cold, and being damp makes them worse.

It can be worthwhile insulating the inside surface of these walls, particularly in a bathroom, when they are going to be tiled, plastered or redecorated.

@piglet

Thanks so much. I will look into extractor fans, I know I have one in the bathroom but I probably need to update it to something more powerful.

In terms of the kitchen I only have the hood above the cooking hob, no extractor fan in the wall, that would involve I assume making a hole in the wall

How will I be able to tell if the extractor hood above the cooking hob is powerful enough?

Boil a large pan of water and whack on the extractor and see if all the steam goes. A lot of people won’t use full power because of the noise, so even on lowish setting you want it extracting well.

If it is a reirculating hood, it removes no steam at all. It is just an ornament.

@PigletJohn
Thanks for your help - i went through all these points with the builder from the residents association following his initial recommendation but I think now he has got scared and run off! I cannot get hold of him any longer! I think he wasnt keen on the level of detail/challenges - is there any other way of finding a reputable builder to look into this? Or would a plumber also suffice with tests etc? Just unsure which direction to go in now...

The hole through the wall is made with a Core Drill, which is very big and heavy.

Plumbers use them to make 110mm holes for soil pipes (and smaller holes for waste pipes) and electricians use them for extractor fans. Modern cooker hoods are usually 125mm, some are 150mm, so if you're having holes made, I'd go for 125 rather than 100. The hole should immediately be sleeved with a plastic duct, and if a cavity wall, mineral wool insulation stuffed into the cavity. A vent cover (I recommend the Cowl type) is fitted on the outside. At high levels, there are some that can be pushed through from inside to save getting scaffolding. If you are not yet ready to fit the fan, you can fit a hit and miss cover on the inside for controlled ventilation.

General builders also have them.

Bank robbers use a bigger version to cut a round hole into a vault.

You can hire them, but unless you are unusually strong, and capable of doing heavy work off a ladder, I would not recommend it. A smaller hole for a waste pipe is OK. If you are going to the trouble, I would have all the holes you could possibly want done on the same day. I did two tumble driers, one cooker hood and two extractor fans in a day on my own house. Even if you don't have a tumble dryer that needs it yet, it will be very simple to use if you get one in future.

If you're having a cooker hood or bathroom fan, an electrician who does heavy drilling might be best, so you can have it correctly wired in.

The core drill cuts out a round plug of brick, not like an ordinary drill. It is somewhat noisy and dusty.

@PigletJohn thanks so much for your comments. they are very useful regarding the extractor fan.

with regards to the inside wall being damaged by external pipework etc, i had a local builder lined up from my residents association, but when i went to all the detailed points about excavation etc he has now ran off. what would be the best way to find another reputable builder or do you think i need a plumber to run tests etc on the pipes to find root cause? thanks again

Cruise around the area looking for houses where building work is being done. Make a note in your diary of the address and the work. Ask the builder for a card and say you will be having some repairs (but not yet as you are short of money. This will discourage the ones hoping go loot you). Do not let them see your Ferrari. Avoid itinerants and people who do not live locally or seem to have no address or local landline.

Cruise round again after a month or two, to see if it seems satisfactory, or if it never got finished, and try to engage the homeowner in conversation.

Homeowners will have only vague ideas of what things should cost, and may not be able to gauge the quality of work, but will often realise if something is awful, or if he charges for a day's work but disappears for hours. This is why personal recommendation is best, but not reliable. Work that you can't see, such as on a high roof, or wiring hidden behind kitchen cabinets, or drains under paving, may not be very good.

@PigletJohn thanks so much pigletjohn. I managed to get back through to the old builder, the builder that did the original rendering for proten which has now salts coming through is still saying i have rising damp...

I am confused, can all the cracked pipework outside and moss growth etc cause water to seep into the internal wall and cause flaking paint and salts etc? But if Proten had did injections and rendering shouldnt this be blocking out the water from cracked pipework etc?

I am being told to call proten out to re-render the internal the wall for a third time but go higher up which i dont understand why does it keep having salts coming through...is the leaking pipes the root cause? in which case its not rising damp and why is the render they have done which is apparently supposed to stop damp/water flaking and having salts come through?

Have you actually had the drain exposed and dug out yet?

I have zero confidence in silicone injections. They will not repair building defects.

Did they work the first time?

Did they work the second time?

Do you imagine they will work the third, fourth and fifth times?

OP seems to suffer from selective deafness. I'm still wondering what the "small" is 🤔