Garage dehumidification

[Welshman]

How have we gone from sorting out some condensation in a garage to making it a full blown heated room?

It’s a build up of moisture over time which has become trapped due to inadequate ventilation. Condensation is just an imbalance between moisture and ventilation. It’s normal for a bit of moisture to get in as long as it can get out again.

You obviously missed the part where the OP stated water was be driven in through the brickwork in bad weather. Ventilation alone won’t sort that out and warm air condensing on cold tools will cause them to go damp and rusty.

why not spend that little bit more money to ensure it doesn’t happen for any reason and keep the expensive equipment dry and rust free.

 

[b0rn2sk8]

No I didn’t miss it, it’s an assumption which may not be correct. Most garages in the U.K. are built in this way, if driving rain was actually the issue most garages would look the same as the OPs every year but they don’t. Condensation like that can be caused with very little water.

It isn’t just spending ‘a little more money’, turning the garage into a warm room is a typical OCUK over the top solution/response when you also don’t actually know what the issue is either.

The first steps for dealing with damp and condensation are to check for leaks in the roof, blocked getters etc (e.g. to stop excess water getting in) and to check there is sufficient ventilation (so trapped moisture can get out). A small amount of moisture is entirely normal as long as it can get back out when needed. What the OP has isn’t normal. This thread has jumped straight past that to building an insulated room

A well sealed garage will get damp because there is no ventilation. Most garages are not built with any specific ventilation points but most garages built in this way have a very leaky up and over door so moist air getting trapped is rarely an issue.

 

[Welshman]

No I didn’t miss it, it’s an assumption which may not be correct. Most garages in the U.K. are built in this way, if driving rain was actually the issue most garages would look the same as the OPs every year but they don’t. Condensation like that can be caused with very little water.

It isn’t just spending ‘a little more money’, turning the garage into a warm room is a typical OCUK over the top solution/response when you also don’t actually know what the issue is either.

The first steps for dealing with damp and condensation are to check for leaks in the roof, blocked getters etc (e.g. to stop excess water getting in) and to check there is sufficient ventilation (so trapped moisture can get out). A small amount of moisture is entirely normal as long as it can get back out when needed. What the OP has isn’t normal. This thread has jumped straight past that to building an insulated room

A well sealed garage will get damp because there is no ventilation. Most garages are not built with any specific ventilation points but most garages built in this way have a very leaky up and over door so moist air getting trapped is rarely an issue.

So you missed the part were every post has mentioned adding ventilation then, you seem to be picking and choosing which parts you want to read and understand.

also I’m not your typical over clock poster as I’m not really interested in PCs and gaming. I came here as it as a good home/life section with lots of posters asking and receiving lots of questions. Good quality pictures of their work and what seems to me is a good working knowledge of the work they do on their homes and gardens. Not everyone is an IT geek who posts here

 

[Blackjack Davy]

I think as has already realised by the OP, the key to preventing condensation is letting the building breath. You don't seal the building up so much that the only way of getting rid of damp air is to use a dehumidifier - let the building breath, helping to get rid of the damp air.

This is the issue isn't it its damp because of rising damp or damp penetration i.e. leaky roofs etc. Other than fixing the damp/leaks the biggest thing is ventilation get some air moving through the place. Looking the first picture though theres clearly damp penetration at floor level through the wall base by the look of it.

 

[Akagi]

Garage dehumidification

While I can applaud your efforts to make amends. In this day and age I really don't think that you should've been humiliating your garage in the first place.
It's worse than flat shaming.

feeble.

 

[pp111]

I have a conservatory that suffers the same issue. I use a thermostat to turn on a fan at and below 9 degrees. I use a noctua 200mm fan, which consumes 1w. Taking in to account power supply losses and all in all it is less than 2W. It works perfectly, keeps the conservators dry all winter.

 

[Scuzi]

So I had an architect friend have a look while he was dropping off an Xmas card. He thought ventilation wouldn’t cut it alone. His recommendation for a ‘proper job’ was to batten, 75mm insulation for the walls and 100mm for the ceiling. Ballpark estimate for a DIY job was £1.5-2k.

That’s more than I want to spend and I don’t want to lose the space. Realistically I won’t be able to do it until next summer anyway so still leaves me with the problem for the next 3-5 months.

I continued looking for other options and spotted this:
https://www.machinemart.co.uk/p/ecor-pro-dryfan-8-dh800-8-litre-deciccant-dehu/

What do you think? Would putting something like that up in the rafters keep the condensation at bay? I get that it would be “dehumidifying the world” but the garage is relatively air tight so maybe it would be enough?

 

[SPG]

Just a get a fan on a timer to spin up for 10mins every hr. Save your money and it properly in the summer.

Oh and seal the bricks now !

 

[b0rn2sk8]

I still don’t understand what help insulating it will make unless you decide to actively heat it which is complete overkill unless you need to heat it for something specifically. All it will do is just slow down how quickly the garage cools but it will eventually cool and hit the due point causing the condensation.

Insulating it will make it even harder for any trapped moisture to get out.

If water is genuinely getting driven in with driving rain then that is the first thing to fix. Stopping excess water getting in followed by increasing ventilation to let any moisture out which becomes trapped will likely solve the issue and cost a fraction of what’s being suggested with no lost space.

You should do all the other normal checks to make sure the ground around the garage isn’t higher then the inside of the garage, leaking gutters, splash back from pavements etc first.

 

[JayMax]

I'd go for the simple and cheaper options first to see if it makes an appreciable difference.
Some airbricks in the walls providing a crossflow of air.
Some Waterseal on the exterior brickwork
Maybe a £30 workshop fan from Toolstation to force some airflow.
You'd have change out of £100

I wouldn't be putting anything on the inside walls (other than tanking slurry or similar) until you've addressed the penetrating damp coming through the brickwork.

 

[jellybeard999]

The problem with ventilation is if it's humid outside, say 70%, surely it will only bring the humid air inside and it won't go below 70%. If the garage is dry and fairly air tight, a dehumidifier could keep it at a lower level.

If there is damp, or a leak, that's a different matter. Resolve the issues first.

 

[Welshman]

So I had an architect friend have a look while he was dropping off an Xmas card. He thought ventilation wouldn’t cut it alone. His recommendation for a ‘proper job’ was to batten, 75mm insulation for the walls and 100mm for the ceiling. Ballpark estimate for a DIY job was £1.5-2k.

That’s more than I want to spend and I don’t want to lose the space. Realistically I won’t be able to do it until next summer anyway so still leaves me with the problem for the next 3-5 months.

I continued looking for other options and spotted this:
https://www.machinemart.co.uk/p/ecor-pro-dryfan-8-dh800-8-litre-deciccant-dehu/

What do you think? Would putting something like that up in the rafters keep the condensation at bay? I get that it would be “dehumidifying the world” but the garage is relatively air tight so maybe it would be enough?

He’s talking crap.....now way would it cost that much to board, batten and insulate

 

[Scuzi]

I’m tempted to just try an extractor fan and some airbricks to see what that does. Trouble is that I’ll have holes to plug if I do go down the insulation route.

So the temperature here now is 13C. The dew point is 12C. Everything in the garage is soaking because it was colder over the past few days meaning that all of the surfaces are below the dew point. The more I think about this, the only way out of this is to make sure the temperature of the air and the contents of the garage stays above the dew point.

 

[JayMax]

You may be right, I'm not an expert - but I'd try the cheaper and simpler options as my first action.
Unless the garage is hermetically sealed then outside air will get in?
A dehumidifier would run at 300-600 watts depending on mode of operation?
How hard does your Meaco run to keep the garage dry? Any ideas on how much electricity it's using?

FWIW my anecdotal story - due to bad driveway drainage my standalone garage gets a very wet floor when it rains. It also has a corrugated asbestos roof, with no sealing around the corrugations where it meets the wall, so plenty of ventilation.
I've never once had condensation in there.

 

[Scuzi]

He’s talking crap.....now way would it cost that much to board, batten and insulate

He normally deals with more affluent folk than me

 

[JayMax]

Trouble is that I’ll have holes to plug if I do go down the insulation route

If you take the brick out in it's entirety for airbricks you can keep it and put it back in place at a later date?

 

[Welshman]

He normally deals with more affluent folk than me

Then he’s ripping them off.....I fully insulated a 3.5mtr x 2.5mtr man cave with Board, batten and insulation for a few hundred pounds....plaster board is as cheap as chips these days and double foil sided insulation is too......trust me I know

 

[Scuzi]

Then he’s ripping them off.....I fully insulated a 3.5mtr x 2.5mtr man cave with Board, batten and insulation for a few hundred pounds....plaster board is as cheap as chips these days and double foil sided insulation is too......trust me I know

What insulation did you use and where’d you get it from? He recommended at least 75mm for the walls and 100mm for the roof. The roof insulation would go on the pitched surfaces to maintain loft storage.

 

[Welshman]

What insulation did you use and where’d you get it from? He recommended at least 75mm for the walls and 100mm for the roof. The roof insulation would go on the pitched surfaces to maintain loft storage.

Double side foil insulation at 50mm......it’s not a house. Local builder suppliers it was around £6 for 1200x450 board and I used around 25 boards with cutting around windows and doors, about 30 2x1 battens £1.40 each and around 10 sheets of plaster board 2.4mtr x 1200 £7 each...

so that’s £265.....give or take and a box of dry wall screws

 

[Scuzi]

Double side foil insulation at 50mm......it’s not a house. Local builder suppliers it was around £6 for 1200x450 board and I used around 25 boards with cutting around windows and doors, about 30 2x1 battens £1.40 each and around 10 sheets of plaster board 2.4mtr x 1200 £7 each...

so that’s £265.....give or take and a box of dry wall screws

Not bad at all.