Help Needed - Condensation

Ventilation, ventilation, ventilation. You must ensure there is an adequate air flow in and out the room. I find leaving a window slightly open at night helps immensely but it can be a bit chilly.

What Malky said plus number 3!
What you're describing is mildew caused by inadequate ventilation.

Check to see if you are getting condensation on the inside of your glass windows - if so the humidity is is 100%. Leaving windows open is chilly, & can cause more humidity problems then it solves.

I solved my condensation probs with a dehumidifier.
Traditional units use a compressor & are noisy, but there is an alternative using a desiccant wheel system, which is much quieter.

There is a company called Meaco & their website contains lots of info' I think you will find useful ...

http://www.meaco.com

I got my dehumidifier (a Prem-I-Air PRDHZ80U) from Meaco in Sep '07. It's worked really well & is quiet, & the service & VFM from Meaco were both excellent.

When we installed double glazing (new frames with proper draught seals) in our house we had condensation problems. Installed a whole hose ventilation system that pumps in air from the attic, or a plenum chamber created beneath the south facing slate roof. Pretty much sloved the problem although if there is an area of wall that doesn't get circulation such as behind the piano then it can still get a bit mouldy. All I need to do now is train SWMBO to use the tumble drier rather than the radiators!
It cost about £1500 all in but with even moderate sunshine it starts to pump the warm air from under the slates into the house. Manufacturer was www.nuaire.co.uk.
Willy.

quote:

Originally posted by Willy:
When we installed double glazing (new frames with proper draught seals) in our house we had condensation problems. Installed a whole hose ventilation system that pumps in air from the attic, or a plenum chamber created beneath the south facing slate roof. Pretty much sloved the problem although if there is an area of wall that doesn't get circulation such as behind the piano then it can still get a bit mouldy. All I need to do now is train SWMBO to use the tumble drier rather than the radiators!
It cost about £1500 all in but with even moderate sunshine it starts to pump the warm air from under the slates into the house. Manufacturer was www.nuaire.co.uk.
Willy.

Hi Willy

Been considering something like this for my home so V interesting. Did you install this yourself? If so was it hard? Is the system really silent?

Thanks - John

While you say 90% sure it's not getting in from outside, suggest you check the externals too (guttering above leaking etc), as whilst it should not be any form of rising damp, it could be penetration due to pointing/blown rendering or alike - not always easy to see.

Often, problems become evident a few feet from the cause, so always check a few feet above. Bad flashing (lead work) around chimneys is a regular clause.

Normally it is just the need for internal ventilation & not just heating the room up more (which many do!) -- and many people have blocked up airbricks over time which has not helped!

Be careful around the chimney(s) interally, especially upstairs, to see if any staining is appearing? This is often soot which when damp turns to acid and seeps in to the brickwork. Not hard to fix but annoying.

If you choose to install an airbrick, remember it is best to be up high generally, so the colder airs falls in to the room.

quote:

Leaving windows open is chilly, & can cause more humidity problems then it solves.

How so?

quote:

Originally posted by Malky:

quote:

Leaving windows open is chilly, & can cause more humidity problems then it solves.

How so?

From the Meaco website

"Can I just get rid of it by opening my windows?

This is fine on a nice summers day but in winter opening your windows will just result in you losing the heat from your central heating and create draughts. This is a waste of money and if it is raining will just let more moisture in. You might as well just throw fivers out of the window."

As Mandy Rice Davies nearly said, "they would say that wouldn't they?"

quote:

Originally posted by bob mccluckie:
As Mandy Rice Davies nearly said, "they would say that wouldn't they?"

IME it's true

John,

The £1500 included installation. There are a number of options available. The basic system just pumps air into the house at a constant rate from the attic. This ar is reckoned to be 3-4C warmer than outside. In the version I have they remove the roofing felt and create a chamber about 4" deep behing the slates. Sun on the slates heats the air in this cavity and it is pumped into the house. There are various temperature monitors and the electronics can increase the flow rate if it detects a greater differential between the house and chamber temperature. I didn't do any calcs on the payback of this extra option but there is a clear benefit on a sunny winter day.
Only required maintenance is new filters approx every 5 years.
Have a photo of the installation somewhere I'll dig out and post.

Willy.

Is there a gap between the shelves and the wall allowing circulation behind the books.

The solution to the problem is probably dependent on how you use the room. Is it permanently heated, intermittently heated or never heated. Only heated when drying clothes.

Cavity wall insulation may also help.

View above.

Silver tube in foreground feed from fan into house.
Silver tube up to right feed of hot air from "solar panel". You can see the back of the panel composed of metalised bubble wrap type material.
Grey tube going up is hot air feed from the attic itself.
Grey tube in background is a cold air feed from a roof vent in north facing roof. In theory you could use it to cool the house though up here in the north I haven't needed that yet.
A small thermostat/indicator is placed on a wall below to control heat/cool.


Willy.

quote:

Originally posted by Willy:
John,

The £1500 included installation. There are a number of options available. The basic system just pumps air into the house at a constant rate from the attic. This ar is reckoned to be 3-4C warmer than outside. In the version I have they remove the roofing felt and create a chamber about 4" deep behing the slates. Sun on the slates heats the air in this cavity and it is pumped into the house. There are various temperature monitors and the electronics can increase the flow rate if it detects a greater differential between the house and chamber temperature. I didn't do any calcs on the payback of this extra option but there is a clear benefit on a sunny winter day.
Only required maintenance is new filters approx every 5 years.
Have a photo of the installation somewhere I'll dig out and post.

Willy.

Hi Willy

Thanks very much for the info'.
I'll certainly give this company a call.

Cheers - John

Thanks for all the replies folks. Replying to a few of them:

Happy Listener - chimney was reflashed recently, but there is some minor repointing required close to the problem area (hence my 10%).

Fatcat - I work normal hours, and the room is heated when I'm in the house. There's no gap between the shelves and the wall - guess it would be worth tring to remedy that?

Bob Mc - Will definitely stop drying clothes in there!

Any thoughts on the pros and cons of installing airbricks?

Creating a gap between the back of the shelves and the wall may well cure the problem without spending money. It did so in my bedroom, much to my surprise.
But I'm a skinflint, so I like to try cost-free solutions first.
Ken

Ken, cost-free works for me too!

Before I spent major money I would just move the books away from the wall and stop the laundry drying.

As condensation is where warmer moist air hits a colder surface and the books if they are a leaning on the wall act like sponges.

Air bricks in old houses can be a sod to install due to drilling thick brick walls (AFAIK Victorians didn't use cavities). It's a bit messy (brick dust stains if not careful) but with care you can drill in from either side with a large masonry drill bit and smack bricks out and butter in airbricks. Stay away from boiler flues though.

Suggest you tap around the walls as many people fill airbricks in, thinking they are making the place warmer. Interesting that modern day windows are mainly double glazed, with heat reflective glass and then they go and put a trickle vent in the top!

Another alternative is to dry-line the chinmey breast area with plaster board (dob and dab with adhesive and then plaster up), which acts as a good insulator but some care here as the 'cold wall' will remain behind this.

Often cracking opem a window on opposite side of the room to the room exit or another window works. But careful re house insurance here, as many policies now state you must have all windows locked when out.

Willys idea would not work in my house on account of the fact the loft is stacked high with crap.

quote:

Originally posted by garyi:
Willys idea would not work in my house on account of the fact the loft is stacked high with crap.

You didn't get to see what's behind the camera, let alone what's in the other attic! Got to put those empty Naim boxes somewhere.

Willy.