Help With DPC and Plastering in Rental Property
Damp can be a major issue in the home. Find answers to questions or post your own here.

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Help With DPC and Plastering in Rental Property

by girlie26 » Tue Nov 21, 2023 9:47 am

Hi Everyone
Hoping for some expert advice if that’s OK. I have been the landlord of a property since 2006 and have some plaster/damp issues that I am trying to understand- first post so please forgive my lack of knowledge in advance, but I am trying. To try and be both brief and clear, I list below a timeline of events. However, I still appreciate this post is long as I want to present the full facts, so again apologies.

2006 – I bought the house, 2 bed end terrace, with a ground floor extension. This came with DPC and 30 year guarantee, dated October 2005. Of significance, the guarantee states ‘Any replastering work associated with the Treatment, if carried out by other than the company, shall be strictly in accordance with the companies specification for such works.’
‘Set out below are the areas covered by guarantee number
Front room all walls. Rear room gable wall and party wall.
Plaster to be hacked off to a height of Imtr,and be replaced in a washed sand and cement render at a 4/1 mix with a water repellant added. Drying out time is 12 months.’

April 2014 – the property is now managed by a letting agent as I moved away from the area. The tenant vacated and the letting agent reported damp in the check out report. They instructed a contractor attended the premises and his invoice states he ‘hacked off damp plasterwork to front living room and replaced using a waterproof render skimmed to a smooth finish’

January 2015 – same contractor fitted chimney stack with air vents, as well as vents to the front bedroom (above the front living room) after new tenant reported damp growing behind wardrobe in the front bedroom.

April 2023 – I appointed a different letting agent, who has now been looking after the property since 2016, who informs me the property is damp and he believes it is due to condensation due to the tenant not understanding about drying clothes indoors (young single mum). He suggests getting a PIV installed , clearing the gutters of leaf debris and fitting gutter guards which I agree to. When his contractor goes to look at the property the contractor states
‘The above property was checked for damp issues. Rising, penetrating damp and condensation can be seen on the Gable end wall in the kitchen and behind the kitchen door. These areas had surface moisture but behind the kitchen door there was a hole where I could put my hand behind the plasterboard, it was dry behind the plasterboard yet saturated on the surface and at the bottom of the wall. On the external wall in the kitchen the surface of the wall was wet with small droplets of water on the surface this is consistent with condensation however on inspection upstairs, an internal chimney breast can be seen above the issue in the kitchen so I would recommend an inspection on the chimney stack to make sure water is not running down the brickwork and penetrating the plaster. Inspecting the external of the property the brickwork on the chimney stack has foliage growing out of the mortar beds, this shows there is a moisture in the brickwork/mortar beds because it is sustaining plant life. I would also recommend having the gutters cleaned out as future problems may occur in the property as the are full and can see grass and plants over the side of the gutters.
Condensation mould can be seen throughout the property, advice has been given to the tenant on how to clean and sterilise the growth, additional works will be needed to rectify this issue and will be explained below.
The following works that we can carry out for the property are:
• Floor Protection installed to all floor coverings.
• All skirting boards removed from areas highlighted above and disposed of.
• Damp plaster knocked off to areas highlighted above, bagged up and disposed of.
• A chemical damp proof course installed to the mortar bed.
• Tanking membrane fitted to the walls with plastic pins.
• Backing plaster applied to walls.
• Skim finish applied to walls and feathered into original walls or fully skimmed.
• New timber skirting boards supplied and fitted.
• A PIV+ unit fitted into the loft space, this unit is an air movement unit and prevents mould growth throughout the property.’

My letting agent said he would revisit the property again to take a look at the property again.

June 2023 - I receive this from the letting agent.
Basically, the house is dry at the moment. There is lots of evidence of water staining to the walls, mainly in the kitchen on the gable end. There is also mould in several areas, but its dry and if cleaned off, should not reoccur if the house stays dry. I’ve had a good look at the gable end, and I can’t see any obvious gaps in the pointing that would allow water to penetrate into the house (it is hard to tell from the photos as the light is shining across the wall). There is no plumbing other than radiators upstairs, and the boiler pressure has remained good, so it can’t be a leak from pipework. The water stains are far too high to be caused by a failed DPC (and given the slope the house is built on, I can’t see that water could permeate so high up the wall on the gable end to breach the kitchen floor level. The roof looks intact and in pretty good shape, but the gutters are full of leak litter from the neighbouring tree.

Given the worst of the water staining is on the gable end (which should be the coldest wall of the house), I’m fairly certain that the problem is condensation. The tenant has said she no longer uses a condensing dryer in the house, but she has two young children and lots of washing. I could see maidens in the house, so I’m sure there is lots of moisture being created by the tenant. The weather is good here at the moment, but I don’t doubt that when its colder all the windows will be closed up and the drying of clothes will continue'.

August 2023 – Gutters cleared and guards now fitted, however contractor has an issue fitting the PIV due to limited landing space. Another contractor is due to attend the following week.

October 2023 – chase the letting agent as have heard nothing. He responds with ‘In the end, the original contractor who went in the first place has been back to check on how he would fit a PIV. He says its not a problem However, he did say that although fitting the PIV would help with condensation, he thinks the rising damp in the kitchen should be addressed first. I know we have discussed this before, and on my visit, I did not think there was rising damp in the property. The wall was slightly “addled” but it did not feel damp when I was there. Given its on such a steep hill, I couldn’t see how damp could get to that height, but I am not an expert in this and I do trust the opinion of xx at xxx. He is saying the wall in the kitchen should be knocked back to bare brick and tanked, replastered etc.'

I reply telling him could he get the contractors who did the work back in first in 2005 as it’s all still under guarantee. He kindly does, and they report the following
‘Ground Floor Kitchen
Damp was found to the party wall and gable wall floor to ceiling.
Ground Floor Front room
Party wall.

On inspection to the above areas, a damp course has been installed but the plasterwork carried out has been a dot and dab method this is the wrong plaster to carry out after a damp course is installed. It should be a washed sand and cement render at a 3/1 mix with a 3in1 waterproof added, leaving a gap of 50mm from the bottom of the plaster and the floor to stop bridging of the damp course, then skim finish. If the plasterboard method is used then the walls would need to have a tanking membrane fixed to the brick, then dot and dab plasterboard, leaving a gap of 50mm from the plaster and the floor to stop bridging of the damp course, then skim finish.
After the above work had been carried out then a drying out time for the new plaster is 12 months, during this time matt emulsion paint is the decoration to be used.
Because of the above plasterboard method being carried out it's not to the our specifications and means the damp course guarantee is invalid unless the plaster is carried out as mentioned above.’

I had no idea there was different method of plastering required for the DPC. Nor did I instruct the contractor to go ahead and remove the plaster from the living room in the first place, this was done without my knowledge by letting agent. Although being honest, I am not sure I would have had a clue anyway.

So, I think (!) my questions are:
1) Would the incorrect replastering of the living room affect the kitchen area party wall and gable wall at the kitchen end?
2) Although I have no reason to disbelieve the original contractor, how would I check the plastering is dot and dab?
3) As you are all aware, there are so many disreputable damp companies looking just to sell their products and services, do you, in your professional opinion think the solution offered by the new contractor is reasonable?

I have attached a roughly drawn a floor plan

Hoping to get this sorted asap so thanks for any help!
House layout .jpg

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Re: Help With DPC and Plastering in Rental Property

by stoneyboy » Thu Nov 23, 2023 11:07 pm

Hi girlie26,
That is one hell of a post.

2005 - It is very unlikely that the original damp proof contractor did not render the walls as per their spec. They are not going to issue a guarantee unless it’s been done correctly.
2014 - it is difficult to understand why hacking off plaster in front room has been done without identifying the cause of dampness.
2015 - presumably you asked for a chimney stack to be installed.
And 2023 - only clearing the gutters has been carried out.

I assume your house has solid 9”walls and that the gable end is in an exposed orientation with little direct sunshine. Rendering the inside of this wall as per the original contractors spec may help to reduce penetrating damp but not with condensation. You can tell if dry lining (dot and dab) has been used by tapping over the wall. If you find regularly spaced hollow sounding areas it’s most likely dry lined and this is useless for a damp wall.

It is very common for damp and mould to appear behind a wardrobe in a bedroom especially with solid walls.

Tenants like their rented property to be warm and draught free. In the majority of cases they do not like spending their money on heating so do not open windows letting in cold dry air, do not use extractors in kitchen and bathroom, and will seal up any draught creating features eg vents, trickle vents. PIV systems are one solution but in the winter these will introduce cold air, a heat recovery type PIV could be used but who pays the running cost?

In answer to your questions:
1 . definitely not
2. explained above
3. Unanswerable question - but why does the damp course need doing again?

I suggest you sell up and let someone else deal with the issues.

Regards S

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Joined: Mon Nov 20, 2023 9:57 am

Re: Help With DPC and Plastering in Rental Property

by girlie26 » Sat Nov 25, 2023 9:24 am

Thanks for your kind reply stoneyboy, really, really appreciate, especially as you say it was a hell of a post. Apologies I just wanted to give full facts, well as much as I am aware of them.

Chimney stack was already there.

I think they are saying the damp course needs doing because there is rising damp in the kitchen.

I have never seen pictures of the damp so think i need that as a way forward then probably to instruct a building surveyor as opposed to a 'damp specialist'?

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Re: Help With DPC and Plastering in Rental Property

by stoneyboy » Mon Nov 27, 2023 12:01 am

Hi girlie26,
The fact that you live remotely means you are very much in the hands of your letting agent and their contractors. Your April 23 letting agent seems to have a more realistic assessment of the damp problems.
The original DPC contractor treated the party and gable walls in the rear room and your letting agent thinks the gable wall is dry behind the dot and dab boarding.
I would suspect a lot of the damp problems in the rear room are as a result of the two moisture creating activities ie bathroom and kitchen, being in this area.
If you do get a building surveyor in make sure they are aware that the with the exception of the rear kitchen wall all other walls have had a DPC installed.
Regards S

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