How to make a hole for fresh air through a 40 cm exterior wall?

[anders07]

With the new Nivell system and mechanical exhaust, we have found that we need more supply air as there is now a significant negative pressure in the house.

We have brick-clad lightweight concrete exterior walls over 40cm thick. A layer of brick on the outside.

How do I make a hole through this in a good way?

Is there a hole saw (that doesn't cost thousands) that can handle it?

Best regards,
Anders

 

[Noseone]

There are valves that can be placed in window frames.

You can always rent tools.

http://www.verktygsakuten.com/diamant-och-karnborrmaskiner

 

[gadeberg]

Otherwise, you can drill a lot of small holes in a circle with a smaller drill. Alternatively, rent a kärnborrmaskin.

 

[Mackan999]

Rent a core drill or a guy with a core drill.

 

[anders07]

Thanks for the suggestions... I had already called around to some rental companies, but none have such a long (deep) hole saw. I want to get through with one of these: http://www.bygghemma.se/inomhus/var...n/vaggventil-tilluft-fresh-tl80f-dbs/p-166941

The hole needs to be 125mm in diameter, and the ones I spoke to have saws that go 150mm deep, but with that I won't get through even if I drill from both sides...

The exterior wall, including brick, is 400mm thick.

Best regards,
Anders

 

[anders07]

Apparently the landlords have extensions... I have now found the machine and drill!

//Anders

 

[AndersS]

But wait now. You can drill the lightweight concrete wall with a regular hole saw, and here I usually use an extension found in a socket wrench set and a socket of suitable size for the hexagon profile of the hole saw, easily reaching 300-400mm. So you drill a hole straight through the wall with an installation drill, also angling it slightly so you have a slope towards the outside for any condensate water. Then it's just a matter of using a 127mm hole saw in regular bimetal from the inside in the lightweight concrete, costing about 125;- + fasteners, until you reach the brick wall. You then need to drill through the brick from the outside, and I would think the hole saw can handle this as well since brick is porous, unless you have some other facade stone that is just called a "brick wall".