Core drilling 2 holes close togeather

[ben1979]

I need to core drill 2x 5" holes below floor level in a internal wall to provide air flow.

The room I'm working in has a solid floor (excavated) and 110mm Pipe will run through. A suspended floor is on the other side of the wall in question.

Very limited on space here I have a space about 12" vertical by a maximum of 22" horizontal to work in. The wall adjoins an external wall to the left.

Question is, where would be best to position the holes? Side by side would seem the obvious option, but would stacking them vertically be a better option?

Thanks for any thoughts on this.

 

[JohnD]

Drill the pilots first.

I would have thought side by side.

Water vapour is lighter than air so tends to rise to the top.

 

[endecotp]

Water vapour is lighter than air so tends to rise to the top.

John, you post this regularly but I’m not at all sure that it’s true.

My understanding is that diffusion dominates over gravity by a large factor, resulting in uniform mixing.

 

[JohnD]

Clouds and bathroom ceilings show the water vapour rising,
.
I don't know if his subfloor will have a lot of air movement.

 

[endecotp]

Clouds and bathroom ceilings show the water vapour rising

Clouds show that it is colder higher up, so the water vapour condenses into water droplets.

 

[ben1979]

Subfloor has very poor air movement hence the need for this work. Not so worried about the height in regard to where the water vapor is higher although I think higher and therefor closer to the joists is probably preferable. Presumably it's negligible though and increasing airflow is the priority.

It's more a question of strength regarding the wall. Options would be 2 holes with about 4" - 6" of brick remaining between them. Is that better horizontally or vertically?

 

[endecotp]

I don’t think you need to worry about the strength of the wall, for these holes.