Condensation / Damp - What to do

tadgh_99

Hi,

Been in the process of prepping a house ready to rent out (or sell at a later date).

However, after stripping off the ghastly wall paper, I've found what appears to be condensation or damp in a below ground utility room (it can only be used as storage or utility room due to building regs).

Foolishly, I had it decorated by a local decorator who just filled some of the ruined render and painted over with some vinyl paint saying that would kill all the damp stains. Two days later the plaster (Easi-Fill) he used to patch up the internal render blew.

He came back and refilled it and so far, no problems.

Less than a month later, I find black mold appearing (just a few spots). So I decided to get some professionals around to give their opinion on what could be causing it and what the solution could be and their findings are;

Specialist 1
Pretty sure that it is condensation because of the tide marks on the wall and that the skirting boards are all ok. Didn't use a damp probe as he said they give a lot of false positive readings. His recommendations were;
- Increase the ventilation in the room
- Get a dehumidifier
- Paint over with stain stopper

Specialist 2
Using a two pronged damp probe, stated that the problem was condensation as the damp was patchy at best. He wouldn’t recommend tanking as a solution as that would only stop moisture coming in from outside and have very little effect on the condensation. His recommendations were;
- Increase the ventilation in the room
- Get a dehumidifier
- Paint over with Anti-mold paint

Specialist 3
Again, pretty sure that it is condensation, but with an element of penetrating damp. Used a two pronged damp probe. Options to resolve it included
- Seal the existing wall with membrane then dot and dab plasterboard on top of it
- Partial repair of failed render (he wasn’t keen on that one)
- Remove all render, place membrane, re-render and and fit sump & pump solution

Specialist 4
Again, used a two pronged damp probe and felt that there could be condensation but the state of the plaster indicates that there could be something more behind the problem. Options suggested:
- Fit heat exchange fan to reduce condensation, apply salt neutraliser to the walls and paint using anti mold paint
- Remove all render, place membrane re-render and fit sump & pump solution
- Seal the existing wall with membrane then dot and dab plasterboard on top of it

Specialist 5
Came along this morning with equipment that can only be described as a bit more complex than the others (including an infrared heat camera and a non intrusive damp detector). Tapped on various points on the walls and pointed out that where there was a hollow sound means that there could be condensation trapped in the cavity.

We had a look through the camera and can definitely see where there is moisture coming in (in one of the bottom corners of the room). His recommendation;
- Remove all the existing render back to brick, apply membrane and re-render

Now I have opinions from five damp proofing people (albeit a lot of the solutions are similar).

As this is going to be a rental property I was going to go for the heat exchange fan / salt neutralizer / anti-mould paint option and hope it doesn’t come back.

But the more I think about it I think the re-rendering option may prove to be the best economy. I may spend all this time & money doing a short fix, but there's no gaurantee it wouldn't come back. Should I want to sell the house in the future I know this will be picked up by any half decent survey which will reflect in a reduction of the house value.

Confused...

Any thoughts anyone?

fairy_lights

I think you should apply the membrane and re-render. It might be the more expensive option but should be the better fix in the long run - also if you can afford to get FIVE damp experts in then I'm guessing you can afford the work

tadgh_99

They didn't charge for advice. If I wanted a full survey then they would have (and I would have expected it)

Sledgehead

A question : does the utility room have a separate utility supply, and if not:

1 ) how do you envisage the electricity costs of such a space (dehumidifier, sump pumps) be paid for?

2 ) how will you ensure the tenant won't turn off such measures to save on electricity bills?

Aside form these issues, I might point out that many people whose walls are entirely above ground suffer from damp problems, either from condensation, or with increasing frequency, from wicking from the exterior leaf due to cavity wall insulation. Given that these folk have problems, can you really expect the space to ever be maintenance / cost free? Your room is likely permanently below the water table. If whole houses that get flooded merely once a year get abandoned, why cling to the notion that this room is anything but a write-off? My advice : fit a sump pump and seal the room off.

tadgh_99

A question : does the utility room have a separate utility supply, and if not:

There's no separate utility supply unfortunately

1 ) how do you envisage the electricity costs of such a space (dehumidifier, sump pumps) be paid for?

Either by the tenants or the new owners. There is a dehumidifier in there at the moment, but that's temporary one. I've also fitted an extractor fan (with humidistat)

2 ) how will you ensure the tenant won't turn off such measures to save on electricity bills?

Very good question, that I will have to think about.

can you really expect the space to ever be maintenance / cost free?

Not at all, I expect there to be maintenance costs along the way. As there are with any other part of a house.

fit a sump pump and seal the room off

An option I had considered, but the boiler & immersion tank are located in that room, so I wouldn't really be able to seal it off (would cost an absolute bomb to relocate everything and then I would have lost space in the house)

fairy_lights

If you're going to be letting the house then I don't think the dehumidifier/pump option is really viable long term.
As a tenant I wouldn't want to pay the electricity costs for keeping a property damp free, I would expect that to be the responsibility of the landlord.
If you can't just block the room off completely then you need to look at longer term fixes.

tadgh_99

I'm slowly coming to the conclusion that the membrane / re-render is the only option.

I wouldn't expect the tenants to pay the costs for keeping it damp free, but I would expect them to pay for the electricity for the humidistat extractor fan.

And if they do turn it off and it causes damage then I would expect them to repair or pay for the cost of repair. That will be in the tenancy agreement (the fan has an onboard chip to record all activity). But that's for a different thread.

Sledgehead

tadgh_99 wrote: »

I'm slowly coming to the conclusion that the membrane / re-render is the only option.

I wouldn't expect the tenants to pay the costs for keeping it damp free, but I would expect them to pay for the electricity for the humidistat extractor fan.

And if they do turn it off and it causes damage then I would expect them to repair or pay for the cost of repair. That will be in the tenancy agreement (the fan has an onboard chip to record all activity). But that's for a different thread.

Good luck with all that. See, you have no right to monitor their use of a fan in a property they are renting, anymore than you have the right to record their land-line conversations of spy on them with IP cams. You could of course askk them if you can monitor such activity, and they may agree, but once they find out he costs of dehumidification etc (which will be apparent from the electricity bills) they will likely 'arrange' for the monitoring to fail, or merely declare it to be faulty (and you are then stuck with setting a legal precedence of allowing such information to be admissible in a court of law).

Besides, your expectations sound far from reasonable. Damp penetration / condensation is a "state", not "dry with dehumidifier working". Aren't you supposed to rent a place out in state fit for such purposes? I think the leckkie is your way of getting around the rules, and thus your responsibility.

princeofpounds

Personally, I would try simply to open up some ventilation channels first of all (I would just say airbricks, but given it is below ground there is likely to be a different appropriate product). It will be cheap, and may help a lot.

Then make sure that the door to the rest of the house it well insulated.

If this is just a utility space, and doesn't have too much of a damp problem with ventilation, then you might not need to have it heated up to full interior standards.

If that doesn't help after 4-6 weeks, then I'd look into more expensive fixes.

tadgh_99

Sledgehead,

See, you have no right to monitor their use of a fan in a property they are renting, anymore than you have the right to record their land-line conversations of spy on them with IP cams

I totally agree as recording landline conversations or spying on them with IP cams is invasion of privacy and is a direct violation of the data protection act.

The fan itself records whether it is switched on or not and whether it is kicking in at the pre-set against humidity levels. This is manufacturers feature that is designed for fault identification with the fan.

The fan is being monitored, not the tenants.

If, however, after the tenancy, I find mold or the such like and call the manufacturer to download the diagnostics but they show the fan is working correctly but the fan has been switched off which has made the room prone to mold etc, then I would be completely within my rights to ask the tenant to make or pay for repairs.

Damp penetration / condensation is a "state", not "dry with dehumidifier working".

Perhaps, I’ve not been clear enough.

The dehumidifier is a temporary one (as I mentioned before). Used for the purpose of prepping the room for decorating only. It will not be there when the tenants arrive.

There is an extractor fan with a humidstat. That isn’t the same as a dehumidifier.

The fan is staying. It’s there for a reason. The room has fittings for a washing machine and has a sink in it, so it’s partial to humidity just as a kitchen or bathroom would be. A fan should be installed in those sorts of areas anyway (regardless if it’s partially underground or not). If the tenant decides to switch it off, that’s their prerogative. But if switching the unit off causes damage, they pay for it.

Besides, your expectations sound far from reasonable.

The fan (not a dehumidifier) costs 8 pence a day to run. What is unreasonable about that? If they are going to quibble about 8 pence a day, I wouldn’t want them as tenants anyway.

Aren't you supposed to rent a place out in state fit for such purposes?

YES!!! This is what the original thread is about. I just wanted some advice on the best course of action to get to that point.

tadgh_99

Hi prince,

The room is partially below ground.

When I moved in, the airbrick was indeed covered over. I've taken that away now and had the humidistat extractor fan installed. In addition to that, there is a small window that is left on its latch.

Not sure if the door is insulated though. I will look in to that. I do know it's a non standard door size so might be able to insulate it myself?

Improved the ventilation about 3 - 4 months ago which is why I am now thinking I may have to re-visit more expensive options.