123Chris456
Aerospace
- Sep 17, 2024
- 2
Hi all. A note ahead: I am a mechanical engineer, not civil/structural.
We have a single family home in Central Florida. 1-story building. New construction according to local wind proofing/hurricane codes. All outer walls are made of blocks 15.5" x 7.5" x 7.5" (see image: ). Every few feet there is vertical rebar inside the blocks for wind proofing. Inside walls and attic are wood frame. Roof attached with hurricane straps.
The outer, load-carrying, wall is about 9 ft high and we are considering to core drill a 3.5" (90 mm) hole at about 7.5 ft height (for an additional mini-split A/C). I did a test drilling into a single block from the garbage dump, and it seems that quite some of the concrete inside the block will break away when drilling. We may also need some test drilling with smaller drill bits (8 mm) in the area of the main hole to identify where the block sides are (no longer visible), to avoids them. So the actual area affected may be larger than the hole itself.
Would you recommend us to consult a structural engineer for this, or is this fairly standard and unproblematic? It's a round hole, so that make the stress distribution around it more favorable. But I don't know about concrete and safety margins in constructions. The home is meeting local windproofing/hurricane standards, so in addition to pressure from the building weight there might be significant suction from the roof (via hurricane straps) or wall side loads in a storm.
Also, our home is under warranty from the builder and we don't have any specific fine-print what we are allowed to do and what not. Would you reasonably assume that a hole of this size would usually void the warranty in case it develops any cracks in the wall later on? Thank you!
We have a single family home in Central Florida. 1-story building. New construction according to local wind proofing/hurricane codes. All outer walls are made of blocks 15.5" x 7.5" x 7.5" (see image: ). Every few feet there is vertical rebar inside the blocks for wind proofing. Inside walls and attic are wood frame. Roof attached with hurricane straps.
The outer, load-carrying, wall is about 9 ft high and we are considering to core drill a 3.5" (90 mm) hole at about 7.5 ft height (for an additional mini-split A/C). I did a test drilling into a single block from the garbage dump, and it seems that quite some of the concrete inside the block will break away when drilling. We may also need some test drilling with smaller drill bits (8 mm) in the area of the main hole to identify where the block sides are (no longer visible), to avoids them. So the actual area affected may be larger than the hole itself.
Would you recommend us to consult a structural engineer for this, or is this fairly standard and unproblematic? It's a round hole, so that make the stress distribution around it more favorable. But I don't know about concrete and safety margins in constructions. The home is meeting local windproofing/hurricane standards, so in addition to pressure from the building weight there might be significant suction from the roof (via hurricane straps) or wall side loads in a storm.
Also, our home is under warranty from the builder and we don't have any specific fine-print what we are allowed to do and what not. Would you reasonably assume that a hole of this size would usually void the warranty in case it develops any cracks in the wall later on? Thank you!