Ventilation through garage stud walls

[highmcdiy]

Hi guys,

I have insulated my single skin garage by putting up a stud wall in between the pillars of the garage.

I have been advised that I need to add ventilation to prevent the build up of humidity inside the garage. The garage will be kept at an ambient temperature.

There are 4 airbricks in the garage through the single skin wall.

My plan is to add passive vents on the stud directly in front of the lower airbricks and then add extraction fans at the other side of the garage to create Airflow.

For the passive intake vents I was going to simply ensure that I left a rectangular gap in the stud, use foil tape to prevent any moisture getting into the stud round the edges, then fix a louvre or adjustable vent. We live in a very high humidity area and I worried just banging a vent in will introduce issues.

Is that the right approach for this? Should I use another type of vent? Should the vent be inline with the airbricks or staggered?

I am new to this so apologies if I am asking anything daft.

 

[^woody^]

Who told you you need to have air bricks?
Don't you have a window?

You certainly don't require or want four air bricks in a garage. Even if you keep one, is it in the correct place?

 

[highmcdiy]

Hey woody, the garage was built with the airbricks - I believe that is because of building regulations?

They have put 2 at a lower level at the front and then 2 at the back higher up.

My interest is the ventilation within the insulated studs though. The garage humidity level are around 80RH at the moment.

There are no windows.

Any help appreciated

 

[^woody^]

Ventilation in a garage to deal with damp and condensation from permeable uninsulated walls and floor is different to the ventilation requirements of a room.

Bear in mind that ventilation does not itself deal with humidity, and external air in winter can be above 90% for weeks. Plus do you need input or extract ventilation? Air bricks do both depending on the day, even if you don't want them to.

A single 6" air brick is good to make a warm room cold quite quickly. If this is intended to cause air movement, it needs to be diagonally opposite the door, in from a corner and at high level, and you'll need to have a gap at the base of the door to allow air in from the main building.

But I'm not clear what you are trying to achieve with an insulated garage room conversion with no window. Are building control involved?

 

[highmcdiy]

Thanks for your feedback Woody.

The goal is to keep the detached garage relatively warm, reduce humidity and dampen sound.

I am looking to store stuff in there and might put in a partition wall and make one half a workshop.

My main concern is if I seal the garage there is no-where for any potential humidity to go.

Building control are not involved. I just want to make sure I do the best job I can without creating any potential damp/mold issues.

 

[^woody^]

You are better off fitting a fan with constant trickle and boost controlled by a humidistat, maybe a heat-recovery model if temperature and humidity is a concern

 

[big-all]

what form off heating are you planning on and whats the main uses for the space

 

[highmcdiy]

what form off heating are you planning on and whats the main uses for the space

Just an electric heater, it's just for storage and possibly a workshop at one point. Temperatures get down to freezing at winter.

 

[highmcdiy]

You are better off fitting a fan with constant trickle and boost controlled by a humidistat, maybe a heat-recovery model if temperature and humidity is a concern

So no passive intake vent?

Or passive intake vent and this?

 

[big-all]

just make sure iff the fridge freezer makes there way in there they can work properly below around 16 degrees as most wont

 

[highmcdiy]

The more I research this, the more confused I get.

Was thinking about some sort of trickle vents high on the wall, maybe 4? It's a 5m x 5m garage. Not sure what to use in a stud wall for this purpose. Plus I have permeable membrane on the outside of the stud which I would need to cut through.

Plus a humidity triggered extraction fan in the roof?

Can see in bathrooms with no windows an extraction fan is used - the garage won't be airtight due to the up and over doors.

Any help appreciated, am stuck in a ventilation limbo at the moment

 

[^woody^]

If it helps, half of my old garage which is now my tool store/workshop is currently 14°C and 67% RH, has no insulation, no heating, no ventilation, no damp, no rusty tools and no soggy bits of paper or cardboard.

 

[highmcdiy]

It does help a bit, maybe I am over worrying!

Although in my garage right now it's 4 degrees Celsius and 87% RH

 

[big-all]

i think your overthinking it
in your head you are trying to sort every problem in case it happens
most problems will be minimum or not exist
once you have sorted the damp getting in [through the structure]the rest can be sorted as you go

 

[^woody^]

A room within a house will settle to an equilibrium irrespective of ventilation and heating.

So unless you constantly pump loads of water into the air and have condensation issues in other rooms, you really are overthinking over nothing.