Damp from Condensation

Mahsroh

Afternoon all,

I'm sure this is one of those that has been raised on here a million times before, but here goes. Also wasn't sure if this was better in this forum or not so apologies if in wrong place.

It's a rental property, i'm the landlord with tenants in-situ.

Tenants contacted me a couple of weeks back concerned over levels of damp / mould in one of the upstairs bedrooms. Straight away ruled out rising damp due to location and the fact that a rising damp issue had been rectified shortly before I bought the property. Was concerned that it could be penetrating damp due to the age of the building (it's a Victorian Terrace) but always thought that condensation was the most likely cause.

Rentokil went to the property today to survey and confirmed my suspicions. It is due to condensation. It's a two bedroom terrace with two adults and three children living there so there is a lot of moisture being produced. No tumble dryer so lots of clothes drying etc. Thought it was strange that it was specific to one room but Rentokil felt this was normal. It's the only room with it's original cast iron fireplace (others have been blocked up) so with the cold air coming down the chimney it's the coldest room in the house - was originally confused by this as it's my initial reaction was that this should add natural ventilation. Rentokil surveyor explained that with a high moisture content throughout the house the two external walls in the coldest room are gathering damp / mould - makes sense I suppose!

Whilst the tenants could do things to improve the damp issue (opening more windows throughout house for starters) the surveyor did suggest that the general make-up of the building means the issue does need to be addressed. However, some of the figures quoted are clearly on the high side:

Currently no extract fans in kitchen or bathroom - suggested one is installed in each with I totally get - Quoted circa £450.00 per room! I'm sure I could get a local tradesman to do the same job for a couple of hundred quid so will look into that.

the one that i'm really not sure about, and hoping someone here can offer some advice. He's quoted circa £1000 to install a centralised ventilation system which automatically kicks in once the humidity reaches a certain level. Sounds brilliant in practice, but also sounds very expensive.

The more I think about this the more I'm thinking I want to install extract fans to kitchen and bathroom, purchase a dehumidifier (though i'd be relying on the tenants to use it) and have a sensible conversation with them about natural ventilation. In addition to this (subject to space) I may also purchase a tumble dryer to try and limit the amount of clothes drying creating moisture. That to me seems like a sensible "middle ground", but I guess what i'm asking is:

a) Has anybody had a similar experience (i'm sure there are plenty of people) and how did you overcome it, and;
b) Does anyone have any experiences with these centralised ventilation systems? Are they worthwhile, and are there cheaper alternatives available?

If it's going to be a significant improvement then it may be worth spending the money, but I can't help thinking i'd be paying £1000 with little benefit to the property overall.

xyz123

Why don't you spend £150 on dehumidifier and ask tenants to run it for 3/4 weeks and see what happens. Clean any mould before running and then see if mould returns in 4 weeks. It must be run continuously. If tenants are concerned about electric bill, please explain to them costs involved and for what it's worth even offer & 10 a month towards running costs if desperate.

Mahsroh

xyz123 wrote: »

Why don't you spend £150 on dehumidifier and ask tenants to run it for 3/4 weeks and see what happens. Clean any mould before running and then see if mould returns in 4 weeks. It must be run continuously. If tenants are concerned about electric bill, please explain to them costs involved and for what it's worth even offer & 10 a month towards running costs if desperate.

That seems a common suggestion from friends and work colleagues too and is an easy fix but I don't think that will solve it long term. It might solve the problem over the coming months but the source of the problem will still remain - and that's where I want to tackle it - at source.

The reality is the house is overcrowded and due to the age of the property and with "modern improvements" (double glazing, blocked up chimney openings, improved insulation) ventilation is poor. A dehumidifier is a short term solution but won't solve the overall ventilation issues.

Three main causes are clearly humidity caused from the Bathroom, Kitchen and Drying of clothes so I think those are the areas that need to be tackled. What i'm really unsure about is whether it's worth spending the "big bucks" on an "all singing all dancing" ventilation system. My gut feeling at the moment is that it's not, but would be grateful to hear others experiences.

ST1991

Not sure if this helps, but we rented a new-build flat beforehand where the bathroom was in the middle (no windows).
There was an extractor fan that didn't do much, and we ran our own plug-in dehumidifier. This didn't really do much, so our landlord installed a new fan with a humidity sensor. It came on with the light, and would turn itself off once humidity was below a certain level. Really helped to sort things out, and never saw a speck of mould on the ceiling or walls after that.

We have now moved, and we have a window in our bathroom at last. But, it still gets very damp in there with no fan drawing it outside. B&Q sell the humidity sensor fans that we had in the flat - so we are planning on buying one and installing it. They are quite reasonably priced, and i'm sure it won't be expensive to install with a local builder. You can also set the humidity level you want it to shut off at too

poppellerant

I would consider doing 3 things:
1) If installing a tumble drier, make sure you install a vent which goes outside that the tumble drier's house attaches to. This way any moisture generated from the drying of clothes is pumped outside.
2) Install extractor fans in both the bathroom and kitchen.
3) Install Positive Input Ventilation (PIV) - these take air from outside and push it inside.
4) Consider the option of installing window vents, if they aren't already there.

Mahsroh

poppellerant wrote: »

I would consider doing 3 things:
1) If installing a tumble drier, make sure you install a vent which goes outside that the tumble drier's house attaches to. This way any moisture generated from the drying of clothes is pumped outside.
2) Install extractor fans in both the bathroom and kitchen.
3) Install Positive Input Ventilation (PIV) - these take air from outside and push it inside.
4) Consider the option of installing window vents, if they aren't already there.

Aside from the last point that's pretty much similar advice that the surveyor gave me...... the issue is that point 3 appears to be a very expensive solution. I.e £1000+. I'm not necessarily against spending that money, but I want to know that it's worthwhile.

Windows don't have trickle vents. When I come to replace the windows I will change that, but don't want to change it until windows are "life expired".

I think I may go with the point 1 and 2 options (as well as providing a portable dehumidifier to the tenants) as this should eliminate the main sources of humidity / damp and if the problem still persists then I may need to look at option 3 further down the line.

It also requires some common sense from the tenants with regards to opening windows and letting some fresh air in, even in the winter. I will make this point to them.

ST1991 - that does help - thank you. I am planning on getting the fans with humidity sensors.