cutting hole in block wall

[rlarkin70]

Hi all- I just bought a house, it is masonry contruction (block) and so is the detached garage. The washer/dryer are located in the garage. Currently the dryer does NOT have an outside vent, it simply has a flexible tube exiting the dryer with a cut-off piece of pantyhose banded over the end of it. This lays on the floor a couple feet from the dryer. I would like to vent it to the outside. To do this I will need to cut a square hole in the block wall and install a dryer vent.
What is the best way to cut the block to do this? Would I cut a large hole and then frame it up somehow to house the dryer vent? If so, what is the best tool/procedure for cutting the hole in the wall.
Thanks for any help,
-Ron

 

[CraigFL]

If your block is big enough and isn't filled, somtimes a swat with a 10+lb sledge hammer is all that's needed for a 4" duct hole....

 

[glennjanie]

Or, for a more controlled break. you can use a 20 oz. hammer. It takes a lot of licks but the block will begin to pulverize soon and you can control what you want to break out.
I don't understand why you wanted a square hole; dryer vents are usually round 4" pipe.
Craig mentioned a legitimate consideration; is your block filled with concrete? I know that many of the houses in Florida are, and even have reinforcing bars in them too.
It is possible to break out half a block, place a sleeve of PVC pipe and concrete around it, then you can run your 4" aluminum pipe through the sleeve. It makes a neat opening. (make sure your aluminum pipe will slip easily through the PVC sleeve before you start, you may want to use SDR21 PVC pipe for the sleeve. SDR21 is thinner, allowing more inside diameter.
Glenn

 

[rlarkin70]

I guess I just figured it would be easier to cut a square-ish opening and then fit something in there with an opening to accomodate the dryer vent. I haven't measured the diameter yet.
I will take a look and see if the block is filled with concrete, I really don't know. If it isn't I will try the hammer to knock out a block, and that PVC pipe/concrete is a good idea.
thanks!

-Ron

 

[Mephistopheles]

Go rent a core drill. And yes they come in sizes larger than what you need.
If you're intent on making a ugly hole, metal flash interior hole and attach duct to it then intall a flapper vent on the exterior wall. Use nylon anchors and screws.