Wall penetration in foundation - how?

[beerfueled]

I have a vacation home from the late 70s with a masonry crawl space. I need to address the moisture issue, but to access the entire foundation for ground insulation (the majority I can reach through the existing opening) I need to create a larger hole where there is currently just an aperture. What kind of material is the foundation made of? The stones are about 17x20x40 cm and look like in the picture. Any tips on the method/tools for creating the hole?

 

[kenneth5828]

I have a summer house from the late '70s with a masonry crawl space. I need to do something about the moisture, but to be able to insulate the entire foundation (most of it I can access through an existing opening) I need to make a larger hole where there is currently just a small opening. What kind of material is the foundation made of? The stones are about 17x20x40 cm and look like in the picture. Any tips on method/tools for making the hole?

A reciprocating saw usually works, depends on what type of stone it is, for example, you can saw a byggmax with a handsaw.

 

[useless]

I guess concrete block. The easiest way is probably to knock out a few stones until you have a sufficient opening.

 

[beerfueled]

I guess concrete hollow blocks. The easiest way is probably to knock out a few stones until you get a sufficient opening.

Can you drill/knock out the mortar between the stones with something to separate them more easily?

 

[useless]

Try tapping a few times on a stone to see if the joint cracks open. Otherwise, it's probably easiest to break the stones.

 

[beerfueled]

Try tapping on a stone a few times to see if the joint cracks open. Otherwise, it's probably easiest to break the stones apart.

With like a chisel?

 

[useless]

With a sledgehammer.

 

[beerfueled]

With a sledgehammer.

Ok, thanks!

 

[Workingclasshero]

Hi.
A tip is to use a cutting disc and mark where the opening should be.
It will be easier to tidy up nicely afterwards.
If you just make a hole, you can mark it the same way there.
But it gets dusty, so you need to wear a mask and perhaps also protect the facade from the dust.
I promise it's worth the extra effort.

 

[beerfueled]

It was indeed concrete hollow blocks. The sledgehammer had limited success; the stone broke apart instead of cracking at the joints. Instead, I started by making a test hole, 15x15 for a vent, with available tools. Drilled a seam of holes and knocked out with a chisel. It worked OK, will probably try the same method for the larger crawl space to avoid getting other tools.

 

[olofh]

Actually, I want to suggest hiring a drilling company. The times I've used them, they've been ridiculously cheap compared to how much effort it would have been to do it myself. They have proper tools, so it goes quite quickly. You can at least ask for quotes...