Following the prolonged cold Winter, my wife is considering fitting air extractors to her rented flat. (mould/condensation issues).
The obvious priority placing is in the bathroom with part P consequences. One possibility is the low voltage offering from Kair which appears to have provision for humidity stat operation.
The flat was originally heated by warm air ducts from a central off peak store so there is also an opportunity for a centrally located extractor/dehumidifier.
Does anyone have insight to the benefits/drawbacks etc?
Nowhere near enough info to diagnose the problem, which is necessary before any remedy can be suggested.
What sort of heating is there now? Does the place feel warm, or is the heating ineffective? What moisture sources are there? Cooking, baths/showers, clothes drying, ...? When does the condensation/damp appear? Where does the condensation/damp appear? Any idea what thermal insulation is installed? Are there any extractors, ventilators, etc. Has it always been like this? If not, what happened to cause the change?
Depends on how the tenants set the rad. stats but the system is amply sized.
Cooking, baths/showers. Hopefully not clothes drying as there is a condensing washer/drier.
Particularly after a let this Winter.
On upper surfaces of North and shaded exterior walls. Manly bathroom and bedroom.
11" cavity wall only. A tentative enquiry to BG bounced as insulation could only be grant aided if *all* the flats in the block were done.
No extractors. Double glazing has trickle vents. Kitchen has double air brick but buried behind cupboards. Cooker hood is re-circ type.
We thought the CH had solved the problem which had been noticeable with the old air duct/ storage system. However a long, cold Winter coupled with a family and children.....
More ventilation and more heat input but you can't stand guard over tenants. We were arranging a simple bathroom extractor (timed on exit if possible) and realised the added expense of part P. One step further to a heat recovery, low voltage extractor. But are there any *gotchers*?
Because large parts of the old ducting system are still there, a centralised system might be possible but issues such as noise, cost of running a dehumidifier, disposal of condensate, pressure balancing etc. are a bit mind numbing.
I think we should pursue the cavity insulation aspect despite British Gas. I believe the building is based on a concrete frame so the cavities might be stopped at each floor.
I'm not clear if that means you own the block rather than the one flat? If the latter, a plugin dehumidifier is a surer approach than ventilation, and costs less to run and is trivial to install. Condensate is plumbed to a waste pipe
CWI makes a lot of sense. Grants arent necessary to make it pay. Brush strips can be used to retain insulation for shared walls. Adhesive on the insulation can prevent it going anywhere after installation.
CWI won't reduce the water load in the air though, either you prevent/ remove it somehow or condensation is inevitable. The usual simple guidelines like using lids on pans are too often impossible to implement with tenants, but you can dehumidify. A contract clause can state that if disabling climate control equipment causes mould, rot etc they're liable for the damage.
One ground floor flat in a 3 storey block, 60's build. Unfortunately rather a lot of exterior walls.
Yes. The flat has two bedrooms, bathroom, toilet, lounge and kitchen all arranged around a central access corridor. I doubt the practicality of fitting a cheap dehumidifier in the bathroom although air could be extracted through existing ducts to something fitted off the corridor. All the waste pipes are on exterior walls.
Brush strips?
Also, if the cavity is open, the junction is horizontal rather than vertical.
So far it has been superficial mould requiring laborious cleaning.
Up to 85% recovery is claimed for extractor units or is this overly optimistic? I think the bathroom is the obvious start point. Material cost around 200ukp so payback within one months rent.
It certainly won't like a 150mm one then! A few years ago I bit the bullet and bought a 'proper' core drill - though the 'Sparky' brand which was under £150 (IIRC) at screwfix rather than better-known brands at 2 or 3 times the price. Shouldn't tempt fate by saying so but It's still going strong after many dozens of holes of all sizes over the years.
Hmm... Solid floors and across the corridor. Might be able to pick up the washing m/c waste from behind the kitchen units. My only experience of de-humidifiers is the floor standing, wheel about variety. Is something available which would not object to an intake fed from a 4" duct? Discharge could be into the airing cupboard.
These would need to be horizontal, mostly. I intend to follow up on the actual structure as the cavities may already be closed at each floor.
Still got to couple up ducting and bore through internal walls but, yes:-)
Yes. More holes through cavity walls! Might be do-able if there is space over the wall cupboards for the ducting.
Yes. That was the electricians suggestion. Suspended for further noise reduction. Lots of duct but possible. There is a convenient space over the corridor. Are there rules governing positioning of exhaust ducts close to gas boiler flues?
My parents own the middle floor of a 3 flats. They managed to get cavity wall insulation done recently. It just needs the people above and below to have theirs done at the same time. Not everyone paid the same price as my parents did not qualify for a full discount as it is not their place of residence. I believe that they paid £150.
A humidistat fan in the bathroom may be better than a timed fan. And what silly prices have you been quoted for a fan installing?
Although the gas main (plastic up to the meter box) has been bonded, incoming water supply and bathroom piping/metalwork have not.
We discussed fitting an in line ducted extractor with the estimator but, as has been pointed out, any humidistat would have to be in the bathroom itself and back to part P.
Unless it is a very small bathroom or the layout is awkard you can have a humidistat in the bathroom. I realise part P would apply, this in many cases is very little extra cost. Your additional costs are obviously the incoming mains bonding and the supplementary bonding (either lots of wires and clamps or use an RCD for the bathroom electrics). Once the electrics are up to current standards the only extra cost of part P is the cost of registering the work when you do a job.
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