Drilling holes for ventilation in concrete slabs

[adamja]

Hi, I live in a single-story house from the 50s with concrete flooring down to the basement where I would like to make a hole for ventilation to the laundry room (what is called the boiler room on the plan). I'm also considering an FTX system and would need to make another hole in what is called the hobby room on the plan for supply air, with the duct going through the closet up to the unit in the attic.

I'm planning to use 100mm ducts, should I be worried that this drilling will weaken the structure or should it be fine? There are no structural drawings or anything like that, but the flooring is supposed to be reinforced and 12cm thick according to the documents I found. And since there are no structural drawings or similar, I thought I would ask here first before having a structural engineer make an educated guess.

 

[Jansson69]

No, you don't need to worry if you make, for example, a 150mm hole in the flooring as long as it's not in a beam or anything like that. Have you checked to make sure there's no water or electricity where you're planning to make the hole?

 

[Håbbe01]

Hi, I live in a single-story house from the 50s with a concrete slab down to the basement where I would like to make an opening for ventilation to the laundry room (what's called the boiler room on the plan). I'm also considering an FTX system and would therefore need to make another opening in what's called the hobby room on the plan for intake air; the duct could then run through the closet up to the unit in the attic.

I'm thinking of installing a 100mm duct, should I be worried that this drilling weakens the structure, or should it be fine? There are no structural drawings or the like, but the slab is supposed to be reinforced and 12cm thick according to the documents I've found. And since there are no structural drawings or the like, I thought to ask here first before I let an engineer make an educated guess.

Unlikely that a reinforced concrete slab would be weakened by two holes

 

[adamja]

No, you don't need to worry if you make, for example, a 150mm hole in the floor structure as long as it is not in a beam or such. Are you aware that there is no water or electricity where you plan to drill the hole?

Thank you, that sounds great. Yes, the water and heating pipes are visible, so I'm aware of those, and the electricity shouldn't be a problem either, but thank you for the reminder.

 

[adamja]

Unlikely that a reinforced concrete slab would be weakened by two holes

That's what I was thinking too, but nice to hear it from others as well, thanks!