Moisture in the Workshop

[Digit]

I remember reading a similar debate to this in one of the woody magazines some years ago, it was killed stone dead by a contributor in southern Texas.
The humidity during the summer months reach 95%! :x

Roy.

 

[Anonymous]

I have a garage attached to the house and fitted couple of radiators (thrown out by a neighbour when their bathroom was done out) on the central heating system a couple of years ago. the coldest it gets is around 16 degrees and the RH is around 40 to 50% when I have bothered to look.
16 degrees and 38% in there today

 

[PaulO]

My workshop is around 50% most of the time. It is a double garage attached to the house, well insulated. I have compared the RH of the workshop to the main house, and they always seem to have about the same RH. So if the house goes up, so does the workshop. I used to run a dehumidifier in the workshop, but since my experiments showed the same RH in the shop as the house without it, I haven't bothered.

I don't have CH in the workshop. Even when it is freezing outside, it rarely drops below 12C in the shop, and a little bit of electric heat easily takes the chill off.

 

[WellsWood]

Sorry Philly, forgot to check the readings first thing before I put the heating on around 9:00am. Now, at midday it's 14deg C and 57% RH.

Heating in my 6.5 x 4.5m 'shop is a couple of electric convectors and an LPG radiant heater for boosting on cold or windy days like today when the convectors can't cope with the draughts.

 

[Taffy Turner]

Phil,

My workshop is a detached double garage. It is unheated except for when I am in there.

The temperature varies from a min of 2 deg C in the winter up to a max of 38 deg C in the summer (I don't do much work in the summer months!!!)

The humidity is usually around the 60% to 75% range, unless we get a prolonged wet spell followed by a sudden drop in temperature, which causes it to increase rapidly to 85% to 90%, at which point I run the dehumidifier for a few days to bring it back down.

Hope that this helps.

Regards

Gary

 

[lurker]

In a previous "life" I designed Environmental test chambers where RH was strictly controlled.
We used "old fashioned" wet bulb Hygrometers as the digital stuff was hopelessly inaccurate over a temperature range.

Eg - you can get a good digital meter ( £200ish) to read rh accurately at say 20C but the same meter will be miles out at 28 c or 12C

The only decent digital meter (trustable) we had for use over the usual temp & rh ranges cost £5000 !!

So....... I'd take those readings with a pinch of salt.

 

[devonwoody]

I PAID £9.99 for mine, and its giving the same readings as those other forum members in similar conditions.

 

[Nigel]

My workshop is like Chris a small integral garage which remains similar to the house RH with an oilfilled radiator to take the chill off

A relative in Australia wrote yesterday that the ambient temp and RH at night was 23c and 90%, a little sticky as he says,

Cheers Nigel

 

[Losos]

Eg - you can get a good digital meter ( £200ish) to read rh accurately at say 20C but the same meter will be miles out at 28 c or 12C
The only decent digital meter (trustable) we had for use over the usual temp & rh ranges cost £5000 !!
So....... I'd take those readings with a pinch of salt.

Yes, I bought one of those cheap digital temp / hygrometer things and pretty soon found the humidity readings were rubbish 'tho the temp. seemed pretty accurate :?

Anyway, I have a wood burner for heating and lots of insulation. When it's minus 10 outside I can get the temp up to 20 C inside. and the shop seems dry at least I haven't had too much rust on tools etc.

The RH readings from that cheap hygrometer were anything from 45% to 75% also because we are nearly 500 MTs. ASL we are sometimes almost in the clouds which makes for increased humidity.......I believe.

Sorry Philly that probably doesn't help you much. I plan to get a proper hygrometer sometime (Not the 5000 quid one 'tho) so if I remeber will PM you some figures then.

 

[ivan]

Devon's* pretty damp compared with eastern UK where I grew up. Here we need a dehumidifier indoors or we get mould spots on books on the bookshelf and a bit of mildew in the back of the wardrobe. Even in winter with the c/h heating on the dehumidifier is needed to keep RH around 60%. (it runs all year)I gather you risk the above domestic problems if the RH is much over 70% indoors.

Outdoors our RH runs from around 70% in (the ocasional) good weather to 90+% (the usual) when rainy.

We have thermo. and RH meter in the workshop where another dehumidifier keeps the RH permanently between 50 and 60%. (70%+ would mean some rusting) I check my RH meters at ambient temp over a saturated salt solution so I recon the readings are within 5%.

* mid county at ~400ft above sea level

 

[Philly]

Many thanks, Gents! This is very helpful.
Philly

 

[Anonymous]

In a previous "life" I designed Environmental test chambers where RH was strictly controlled.
We used "old fashioned" wet bulb Hygrometers as the digital stuff was hopelessly inaccurate over a temperature range.

Eg - you can get a good digital meter ( £200ish) to read rh accurately at say 20C but the same meter will be miles out at 28 c or 12C

The only decent digital meter (trustable) we had for use over the usual temp & rh ranges cost £5000 !!

So....... I'd take those readings with a pinch of salt.

Very true, designing an instrument to measure accurate humidity electronically, has been a right pain at work - still ongoing too!

 

[Digit]

What's wrong with sea weed? :lol:

Roy.

 

[9fingers]

Philly,

I've sent you a spreadsheet of data collected inside and outside my workshop over the last 4 weeks.

Bob