Hello!
How is it best to make a hole large enough for a chimney in a cast concrete ceiling?
Spent half the evening yesterday drilling for the central vacuum, a tiny little hole in comparison... Rented a special drill, but it still took a long time. I'm hesitant to even think about how to make a much larger hole.
Are there any tricks or shortcuts?? Is chiseling the only option?
/Elin
How is it best to make a hole large enough for a chimney in a cast concrete ceiling?
Spent half the evening yesterday drilling for the central vacuum, a tiny little hole in comparison... Rented a special drill, but it still took a long time. I'm hesitant to even think about how to make a much larger hole.
Are there any tricks or shortcuts?? Is chiseling the only option?
/Elin
Sounds tough. Maybe it's an idea to give a ring to http://www.betonghaltagarna.nu/?
It's likely that you'll need some serious equipment, which could both be expensive and even difficult to rent..
It's likely that you'll need some serious equipment, which could both be expensive and even difficult to rent..
I called the first best hole-cutter in the phone directory regarding a hole for heat transfer through a concrete block wall, they wanted 1250 including VAT for it. I don't know if it would be much more expensive if it were real concrete, but the answer is no further away than the phone!
How thick is the concrete slab and what size hole diameter do you need?
The concrete is 15 cm. I don't really know how big the hole needs to be yet, as I haven't decided on the size of the chimney, but I would guess that it will require about 30 cm.
/Elin
/Elin
Drill closely spaced holes in a circle with a regular sturdy hammer drill and then chisel/knock it away. You don't need any high-end concrete cutting equipment. The reinforcement can be a bit troublesome, but you can handle it.
Oh dear, do you think it will work?
Considering that it took 1.5 hours with the concrete drilling musket wonder, I wonder how it would go to make as many holes as required for the whole circle... But it's worth a try!
/Elin
Considering that it took 1.5 hours with the concrete drilling musket wonder, I wonder how it would go to make as many holes as required for the whole circle... But it's worth a try!
/Elin
It can't be that the concrete drilling thunder is just a small hammer drill. Do you have a real rotary hammer with SDS drills?
If not, you should upgrade the hammer drill before you start drilling.
(explanation:
A "regular" drill with hammer functionality has a chuck where you fasten the bit by either hand or a chuck key. These are totally useless for drilling in concrete.
A rotary hammer has a chuck where you insert the drill bit without screwing the chuck. It’s a quick locking of the bit. This machine is made for hammering. How they are mechanically built, I can't describe. The bits have a so-called SDS/SDS+ fitting)
If not, you should upgrade the hammer drill before you start drilling.
(explanation:
A "regular" drill with hammer functionality has a chuck where you fasten the bit by either hand or a chuck key. These are totally useless for drilling in concrete.
A rotary hammer has a chuck where you insert the drill bit without screwing the chuck. It’s a quick locking of the bit. This machine is made for hammering. How they are mechanically built, I can't describe. The bits have a so-called SDS/SDS+ fitting)
As Fasting says: if it took 1.5 hours to drill a small hole for the central vacuum system, then you have the wrong equipment. With a proper hammer drill/drill hammer, obviously with an SDS chuck, you can drill a 15 mm hole through 15 cm of concrete in less than a minute. I bought a cheap, robust drill hammer at K-rauta for 495 kr that can drill and hammer or just hammer (chisel) - it would suffice perfectly well (considering what rental companies charge for a day with drill wear, etc.). A final tip: make sure you don't have water/sewage/electricity where the hole will be....
I suspect we are talking about different things... This concrete cannot be drilled through in a minute, I'm sure of it! The walls in the house are fine, partly lightweight concrete that's like butter to drill into, but also the more solid cast supporting walls are relatively easy, there you could probably talk about minutes. But the actual vault is something else. Rock-hard concrete with fairly large gray stone clumps in it + reinforcement if you believe the drill core we got out after the last drilling. The drill we used was a sturdy machine with a nearly meter-long drill bit that was attached like a giant Allen key without a chuck. It was supposed to be connected to a water hose for cooling and flushing away the drill dust, but we didn't really want to fill the entire insulation layer under the wooden floor with water, so we watered the hole occasionally and cooled the drill bit in a bucket. This, of course, took some of the time, and additionally, we needed to change fuses a few times...
Anyway, I've requested a quote from a drilling company, we'll see how it goes. Still skeptical about whether we can do it ourselves...
/Elin
Anyway, I've requested a quote from a drilling company, we'll see how it goes. Still skeptical about whether we can do it ourselves...
/Elin