Barn conversion

[stannn]

Looks like you need an infra-red thermometer, Beau.
Stan

[HalcyonRichard]

Hi Beau,
             Agree with A.L. If this is the coldest part of your house then it will be the place any condensation forms. I exteneded my bungalow over about 5 years while was working full time. I had parts of the house open to the loft, some radiators not connected. I had condensation on one wall and was convinced I had a water leak ! As I had fitted all the water pipes and heating I should have realised there weren't any any where near that wall  . They key was making sure all the rooms were at about the same temperature + adequate ventilation. Even a difference of a few degrees with a relative humidity of 50% in the warm part of a house will cause condensation. Could you measure the temperature in the room and in your warmest room ? Also if you measure the humidity it should be 40-60% for normal occupation. If you are using only the log burner for heat then you are almost bound to have differential temperatures unless you distribute the heat.

Regards Richard

[Bodidly]

Have infra-red thermometer and have used it.

Room temp away from problem 22.5c
Foil over wall 19c-20c
Foil were in contact with batten bellow and damp 16.5c
Thin wood support strip nailed to wall plate 15.5c-16.5c
Ceiling temp from apex to corner 22.5c-20c
Room RH 55%
Corner RH 61%
Outside RH 93%

What should I conclude from this?

[HalcyonRichard]

Hi Beau,
            Looks like from a temperature/humidity point it is right in the danger area. Also if your heating is off overnight the wall may get colder than you have measured. Attached is a graph of humidity vers temperature. On this if you have an RH of 50% at 20 C then cool by 10 C you will hit the dew point.           


Any thing above 60% is a danger area for mould. Could you add extra insulation on the inside ? They used to sell polystyrene "wallpaper" a couple of mm thick. Or use celotex  or something similar. I suppose it needs to be reasonably air tight or the condensation may form behind it.

How much and where did you get the infra red thermometer - looks a good piece of kit. Good one Stannn 


Regards Richard

[Bodidly]

Thanks for the help on this one guys.

The temp does not vary much as the stove is kept in over night.
The readings I have taken are after the ply cover is taken off so no real idea what things were like in there before.
On our balcony I have still not got around to putting a cover over the foil and we have no problem here, this adjoins the bedroom where the problem is.
My hope is if I replace the ply top and seal all the edges the warm damp air will not get to the cold surfaces to condense.


The infra-red thermometer is the B&D heat detector. You can get much cheaper ones on Ebay but it was a Christmas present to myself so I got the one with
the fancy lights  

In the main sitting room the wall cover is caulked in I could lift one of these off to see if the problem occurs when air finds it difficult to get to the cold surfaces.

[HalcyonRichard]

Hi Beau,
            I think I want one !

   The graph takes a bit of interpreting. The left hand side gives grammes of water per 1000 grammes of air. The way I use the graph is to look at the green line. This is 50% RH. So if I look at the bottom for a temperature of 20 then follow that line up to the green line this point is 20 C at 50% RH. If you then move horizontally to the red line you get 100% RH at 10 C. i.e. by cooling by 10 C the humidity goes from 50% to 100% and condenses out. This gives a feel for the temperature difference to cause a problem. Spookily you seem to be right in this kind of area.

Regards Richard

[Bodidly]

Thanks for explaining the graph.
I thought I understood it and edited my previous post but now you have explained it to me I really do get it.

If I seal all the gaps carefully the air gap becomes part of the insulation like in double glazing or have I got this wrong?

[stannn]

Here you are Richard, a video of the B & D infra-red thermometer. I have one and it is brilliant.
Stan
http://www.yougen.co.uk/blog-entry/1581/Eliminating+the+draughts+that+push+up+your+heating+bills/?utm_medium=email&utm_campaign=Consumer+newsletter+October+2011&utm_content=Consumer+newsletter+October+2011+CID_5cf7b04033256972d066da837419aeb2&utm_source=Envirosend&utm_term=read+my+review+here

[HalcyonRichard]

Hi Stannn,
                Thanks for that. I am getting one  . I think it will pay for itself pretty quickly.

Hi Beau - It's an art rather than a science. The wall I had water running down was glazed tiles. Right next to these on the same wall was emulsion paint with no condesation at all ?. I think wood is quite condensation resistant. Not sure why. But it could be that the surface finish warms slightly when a little condensation forms and stops any more.  I have noticed porous surfaces tend not to suffer as badly as "glossy or shiny" surfaces. Even a thin sheet with an air gap will raise the internal surface temperature. Could you use gaffer/masking tape so you could check over time. Then do a proper job when you are happy with it ?

Regards Richard

[stannn]

Hmm, the video doesn't work; any ideas?
To my eternal shame, I had to join QVC because their price was only £22.44 delivered. It will not be in the current catalogue but nor was it then........I just spotted a connection on google.
The QVC part no. is 564482.
Stan

[HalcyonRichard]

Hi Stannn,
               You are a star. My better half has just placed an order for me. £22.45 includes postage. Cheapest I found elswhere were all around £ 40 mark with postage. The link works fine for me - just showed it to my better half.

Thanks Stannn

Regards Richard