Condensation help!!

gt568

Doozergirl wrote: »

The first thing is the thermal efficiency of the windows. Anyone is going to have a hard time keeping condensation from single glazed windows, for example.

And the second thing is keeping the house warm.

And ventilation. It's a balance, but a common misconception on these boards is that ventilation trumps everything, which it does not. Double glazed windows should have trickle vents. If houses were built with chimneys, then I'm a great believer that those should be maintained for ventilation as well.

Yet there are plenty of people who say they shouldn't! I don't know what's for the best.

I live in a 4 bed double glazed house and in the cold of the winter we always get (relatively bad) condensation despite ventilating, keeping the house warm and not drying clothes indoors.

Nothing I've tried seems to work. :cool:

Doozergirl

Building regs only dictate that you need to put trickle vents where replacing windows that have them.

But if there is condensation build up then background ventilation is going to be important. It is in most houses. I would always install them unless there was a fully designed ventilation system in place that dictated otherwise. They can always be closed, but trickle vents can't always be retrospectively installed.

Gloomendoom

Doozergirl wrote: »

The first thing is the thermal efficiency of the windows. Anyone is going to have a hard time keeping condensation from single glazed windows, for example.

I'm currently sat in my single glazed (metal framed windows) sitting room with not a drop of condensation in sight.

Doozergirl

Gloomendoom wrote: »

I'm currently sat in my single glazed (metal framed windows) sitting room with not a drop of condensation in sight.

Good for you. I was responding to a direct question.

Older houses were always good at self regulating because they aren't very airtight. But that works, there is good background ventilation. You can have problems when installing double glazing in houses that were designed to breathe and starting to seal houses up.

TheCyclingProgrammer

They can always be closed, but trickle vents can't be retrospectively installed.

We had a trickle vent retrofitted to our shower room window.

Doozergirl

TheCyclingProgrammer wrote: »

We had a trickle vent retrofitted to our shower room window.

Edited. .

greenbee

Doozergirl wrote: »

Older houses were always good at self regulating because they aren't very airtight. But that works, there is good background ventilation. You can have problems when installing double glazing in houses that were designed to breathe and starting to seal houses up.

Too right they're not very airtight... I've got a permanent draught in this house at ankle level :cool: And I can't find where it is coming from.

1980s double-glazed windows were replaced last year with new ones and condensation has moved from the inside to (mostly) outside. I do need to learn to keep the house warm though... I'm so used to it being impossible to keep warm and being conservative with the heating in case I run out of oil that it's taking me a while to get used to the fact that the house is gradually getting easier to heat properly. New windows and new loft insulation have made a difference. As has zoning the heating and probably more importantly, getting someone competent to balance the radiators properly rather than the idiots who installed it...

TheCyclingProgrammer

The cold draft you feel at ankle level but can't find the source of might not be an actual draft, it could just be your feeling the convection current carrying the colder air back towards the heat source in the room.

greenbee

TheCyclingProgrammer wrote: »

The cold draft you feel at ankle level but can't find the source of might not be an actual draft, it could just be your feeling the convection current carrying the colder air back towards the heat source in the room.

Sadly it probably is. By the time it's warm at ankle level I expect it'll be like a desert at head height!

alejamruc

We still had terrible condensation/mould problems in our double-glazed victorian terrace, despite trying all of the regulalry-recommended fixes. We eventually completely fixed it by installing a positive pressure ventilation system (which cost us less than replacing one old double-glazed window). Here's what we learnt along the way via much research, talking to damp specialists and using the new unit through winter:

Modern living produces more moisture. Modern houses are designed to keep heat (and by default, moisture) in. When moisture hits a cold surface it condenses.

The only solutions are to:
- Increase the temperature of those surfaces where condensation is forming
- Reduce the moisture you create
- Get the moisture out of your house once it is created

Getting the external surfaces of your house to a constantly higher temperature isn't easy. Especially if you have an older property (ours has solid brick walls) then heat leaches through constantly. Double glazing is much better than single, but heat still escapes. Heat your house reasonably so your walls/windows are not ice cold all day and night, but turning up the heating is never a complete fix in my experience, and it's a costly solution over time.

Reducing the moisture is more easily said that done. We live modern lives, with showers, cooking etc. Yes, drying washing outside is sensible, but in winter it isn't viable, and condensing tumble dryers are fairly expensive to both buy and run. Do the best you can, but realistically you're going to create a load of moisture through normal living.

Getting moisture out is therefore the best and most cost-effective in my opinion. However, we increasingly seal up our houses to keep in heat, but this in turn keeps in moisture. Opening windows more is the low-tech solution, but you'll lose a lot of heat. Extractor fans are a must, but they don't vent your whole house and their effects are more localised. Dehumidifiers will again help, but they are a pain to always have on, and again their effects are quite localised.

After lots of research (and frustration at trying everything else), we installed a positive pressure ventilation system (also called a positive input ventilation system). We opted for the Nuaire Drimaster Eco Heat model.

It was below zero the day after installation. Normally we would have water pooling on the window sill, but the windows didn't have a spot of mist on them. Also, our bathroom has two exposed walls so the walls would be dripping in water after a long bath. Now, we leave the door open during a bath, put the unit on 'boost' and there are no issues (the most we get is a light steam on the window, but we don't even get a steamed up mirror now). Black mould issues on external walls behind furniture are also completely gone. We also continue to dry washing inside with no problems (in fact, towels on the banister under the vent dry noticeably faster, as does a clothes horse of washing!)

We have put it through its paces in an old house in the depths of winter with people who like to have long hot baths, and I am genuinely astonished by the results. After a few months I am now making a point of getting on some forums to make these things more widely know, as black mould has always been such a battle in every property we've ever lived in and I know it is for so many people.

Damp companies charge around £800-1,000 to supply and install these units, but any vaguely competent DIYer can honestly do it themselves (so long as you have an existing plug socket or light-fitting near where you put the unit). For the Nuaire one we bought, I even found a step-by-step video installation guide on YouTube. We spent about £400 on the unit and I installed it within a couple of hours.

If you do get one, the hallways control unit is a good buy, as you can boost the fan speed for baths/showers etc. As air takes the path of least resistance, you can also get clever at channeling the flow where you want it, by closing doors and opening others (so, during/after a bath or shower we close all other doors expect the bathroom door + turn on the extractor - it then directs the flow there and clears out all of the moisture really quickly).

Just to make clear, I have absolutely no links to any manufacturers/damp companies etc.. I am however searching for threads on condensation/black mould to hopefully make more people aware of this as a solution to something that has pained us and so many friends/family for years.