Forced kitchen unit ventilation …

[Kearn]

Evening all, we’re finally close to a new kitchen being manufactured, only 11 months after designing it!

The room is an old animal shelter, incredibly thirsty old red brick solid 9inch walls. Ground levels aren’t our friend as we’re built almost on top of limestone bedrock, 300mm footings. outside levels aren’t much below inside as they can’t be. And limestone likes to hold onto water or worse still offer it up when it rains!

Floor is ok, RFG with limecrete and UFH which runs to approx the unit edges, but not fully under.

So the walls will get damp from the ground as the bricks love to suck up moisture. They’re not plastered behind units, we’ve left a nice air gap to offset cabinets from the wall.

What I’m designing now is how to force airflow behind and under the cabinets to get the damp air out and dry the walls.

The plinth is a decent height and there will be regular air vents every 500mm or so.

Computer fans on timers are a contender, but how many and where? and do they push, or pull, or both?

On the pic, we have warm appliances, all uncounted counter integrated. Only low level units.
A - freezer
B - fridge
C - dishwasher
D - ovens

What are we thinking?

 

[a twig]

Given your kitchen will have to have a 60 m3/hr vented extract to comply with building regs, will you definitely need active ventilation behind the units?

If there are vents along the plinth and vents/grilles at the back of the worktop you might get enough air movement from that?

 

[Kearn]

The extraction for cooking is one thing, up high doing its thing for steam and smells etc.

My walls are damp, just need to sneeze and they get darker.

There will be vents in the plinth, but not on the work surface.
I’m leaning towards 2 or 3 computer fans or similar, pulling out moist air from under the units and letting the vents equalise.

 

[a twig]

Fair enough. Given air temperature gradients - if you’re trying to pull air out from the bottom you will be fighting natural convection ( i.e. you will be trying to pull naturally rising warmer air which could potentially be carrying more moisture down behind the units which could be more likely to cool and condense on cold walls )

If forced ventilation is your answer I would have thought you’d be better off pushing air from the bottom as it would be assisted by any warmer air coming from the UFH.

Only reason I questioned was because in our kitchen I’ve taken a different route and rather than have a vented extractor hood I have a re-circ hood to take grease etc out then a 60 m3/hr wall mounted extract high up in the wall, so the entire kitchen air can get dumped outside in 40 minutes if I’ve been boiling a lot of water etc and increasing the moisture content.

 

[Kearn]

That makes sense, if there was an exit point at work surface level too - currently, that’s not the plan as I don’t fancy a crud catching trap on the surfaces so my only current thoughts are entry/exit points forced and passive, on the plinths…. Hmmm

 

[a twig]

You could build out a thicker upstand and do the top vents in that as that would lift them up from the worktop?

Will have a further ponder during dull moments at work today and see where I end up

 

[Kearn]

You could build out a thicker upstand and do the top vents in that as that would lift them up from the worktop?

Will have a further ponder during dull moments at work today and see where I end up

No upstands - work surface will be cut into the lime plaster most of the way round, with the exception that we have tiled areas behind hob and sink…

 

[lizziecupcakes]

I’ve taken a different route and rather than have a vented extractor hood I have a re-circ hood to take grease etc out then a 60 m3/hr wall mounted extract high up in the wall, so the entire kitchen air can get dumped outside in 40 minutes if I’ve been boiling a lot of water etc and increasing the moisture content.

i have a 60 m3/hr fan high up in one corner of the kitchen to help get rid of rising moisture and condensation (I have a high kitchen ceiling). I don’t have a cooker hood yet (but will get a recirculating one), for now I open the window and wipe down the cooking areas. I also use a dehumidifier if i’m boiling things.

I would prefer a proper cooker hood that goes to the outside but my cooker is against a partywall and not close enough to the external wall and so it would look ugly.