Mould in an air tight house

[Triassic]

Since we moved into our air tight cabin we’ve noticed a slight Mould problem around the places we remain stationary for long periods, behind the headboard and above the Work from home desk (the wife sits here for the best part of nine hours per day).

 

Any thoughts on what’s going on and the cure?

[Nickfromwales]

28 minutes ago, Triassic said:

Since we moved into our air tight cabin we’ve noticed a slight Mould problem around the places we remain stationary for long periods, behind the headboard and above the Work from home desk (the wife sits here for the best part of nine hours per day).

 

Any thoughts on what’s going on and the cure?

More info please ! 

PiV / Trickle vents / MVHR ?

 

[Triassic]

Only trickle vents at the moment. The cabin is only 35m2. Open to suggestions.

[ProDave]

Insulation level? I am guessing not good as you need a cold surface for moisture to condense and start mould.

 

Having been in the caravan for over a year and through a cold winter, I can assure you you need a LOT of ventilation to keep condensation at bay.  A blast of the dehumidifier from time to time helps dry things out.

[Dudda]

I'd say it's still drying out and not near enough ventilation. It's so small and you are both producing a lot of moisture breathing, cooking, showering, etc. Are you planning MVHR or DCV?

[SteamyTea]

Maybe be worth a couple of very small fans on timers, see if things improve.  If they do then you know it is a local problem and not a general one.

[Triassic]

145mm of Kingspan inside 150mm Timber Frame, walls and roof. 300mm in floor.

Edited May 4, 2018 by Triassic

[mike2016]

A lot of tiny homes have the same issue. I recall that they recommend purging the air by opening all the windows daily. There's an article here worth looking at:

https://tinyhousebuild.com/how-to-save-your-tiny-house-from-mold-and-moisture-issues/

 

Some type of active ventilation will most likely be necessary.....there's one mentioned in treehugger:

https://www.treehugger.com/tiny-houses/leaf-3-tiny-house-designed-seriously-cold-climates.html

http://www.lunos.de/en/product/e_with_heat_recovery/

Less ducts but any active system would help.....you need to move air through the property if possible.....

 

[jack]

You can get through-wall extractor fans that have some heat recovery. They aren't very efficient compared to proper ducted MVHR units, but still better than constantly opening windows to get fresh air in.

 

Edited to add: Missed the previous post - the Lunos unit above is what I was talking about.

[joe90]

Yes our last house which we rent out has the same mold problem, double glazing was installed before we bought it but with no trickle vents!!!. I told them they needed to open windows daily but they don’t appear too.

[SteamyTea]

I think this is an idea opportunity to make a cheap MVHR unit.  Not that hard.

[Triassic]

Great idea, I have some space under the kitchen units. What would I need? Anyone got any design details?

[jack]

Do a search for "DIY MVHR".

 

Someone posted a link to this: http://handmadematt.blogspot.co.uk/2015/01/heat-recovery-ventilation-heat.html

 

Note that this is a crossflow unit, rather than the counterflow approach which is used in commercial units. Crossflow is easier to make, but has a hard limit on effeciency of (from memory) 75%. Real-world will be a lot lower.

[Onoff]

This thread I started?

 

 

 

[SteamyTea]

I shall try and find some pictures of mine.

About time I did Mk3.

[Onoff]

10 hours ago, SteamyTea said:

I shall try and find some pictures of mine.

About time I did Mk3.

 

Please do. Pretty sure you were going to look for me one time.

[SteamyTea]

I was, on your timescale.

Truth is I hate going up in the loft, it is depressing because of all the junk up there.

[Triassic]

On 04/05/2018 at 22:29, SteamyTea said:

I shall try and find some pictures of mine.

About time I did Mk3.

Did you ever find those photos?