Expert: Bruce E. Johnson - 1/30/2010

Question
In my kitchen I currently have a double window in a block wall with stucco on the outside. The window opening is approximately 6' wide and 4' high. the windowsill is 2' from the floor, so I am guessing that I would have to cut the block wall down to the floor. can you give me any information on what to watch out for and the best way of doing it. Also, do you think that I should try and tackle it on my own or hire a pro.

Answer
Hi Mike, Yes that is pretty much it.  Cut the sides, knock out the block and then fill the open cells of the block at the floor with sacrete and smooth it out.  The things to look for are electrical and/or plumbing that may be in the wall.  If you have an electrical outlet in the wall, pull off the drywall on the inside and see where the power to the receptacle is coming from.  If it is daisy chained to another nearby receptacle you can possibly disconnect the power source at the other receptacle.  If the receptacle in the wall you are taking out has power in and power out then it gets a bit more complicated, you will have to figure out a way to reroute the power around the new door opening which may require an electrician.  Be sure to locate the fuse or breaker in your electrical panel and turn it off before working on the outlet.  The same with plumbing, if there is a hose bib on the outside of the wall or some other plumbing related item, it will need to be taken care of also.

As far as cutting the block goes, if you dont mind the dust you can rent a cut saw at any tool rental place, Home Depot and Lowes both rent tools.  Get a 14" saw so you can get as deep of a cut as possible.  Wear protection for your eyes, ears, and a mask for dust.

If you don't mind spending a couple of hundred bucks you can have a professional concrete cutting company come out and they can cut the opening in a heart beat using a wet saw method which keeps the dust down considerably.  Call them up and tell them exactly what you are doing, the length of each cut etc. and they can give you an estimate over the phone.  Most places have a minimum fee of 150 bucks or so.  Your job would fall into that category.

If your budget is really tight and you have a skil saw you can buy masonry blades to fit your saw.  If you do your cutting with a 7 1/4" skil saw you will have to cut it from both sides of the wall.  Again be sure to wear a dust mask and eye protection.  The main part of the cutting will be the existing window sill.  The window sill is probably filled with solid concrete.  Once you get the sill cut through the rest is possibly hollow masonry which can be scored and knocked out with a small sledge hammer. I prefer cutting as much of the block through as possible so when you go to beat it out with a sledge you put the least amount of stress on the surrounding walls, you don't want to be cracking stucco all over the place.

 Once your opening is roughed in you can patch the sides with mortar mix and as I mentioned the bottom with Sacrete.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com