Knocking out concrete blocks for new window

[HoleInTheWall]

I am renovating the basement, and want to knock out concrete blocks in supporting walls and put in a sliding glass door and some big windows.
1) Can I ask window installers to do this, or is it a better idea to contact building contractors? I'm in a bit of a fix--I don't know where to look for this. Are stone masons (i.e. concrete block layers) qualified for this?
2) I have a very expensive quote from a window installer. $25,000 for labor only: hole + 8' sliding glass door; hole + 5' window; hole + 4' window; 6' hole only. This is an expensive area (No. VA); nevertheless, is this expensive for this type of work? I sure hope so, because that cost is awfully big compared to the benefit gained.
Thanks!

[HoleInTheWall]

I guess to make this more clear I should add that the house is on a slope, so that the back of the basement is completely above ground. Have any of you installers knocked a hole in concrete-block walls to install windows? I'd appreciate knowing whether this is a very-expensive project or not. Thanks!

[FenEx]

Sure it will be expensive. You will need drawings and a stamp from an architect or structural engineer. You will then need a contractor that is qualified to support the upper levels of your house during and after the renovations with steel reinforcement.

[HoleInTheWall]

How do I go about doing this? Call:
a window installer?
a general contractor?
an architect?
some other kind of person?
Thanks!

[PK]

I just did one of those this summer lots of paperwork involved between the city and the architect which we had to have incharge of the job. The real issue when you get to the planning stage is going to be headroom above the doors and windows. The inspector is going to want to see properly sized headers, and on a 6'8" door there is not much room left, expecially if your going to raise up the door to prevent water from rolling in the door. Your going to want a GC who has done this type of work before. I know out by me there are GC's who specialize in basements. I have some progress shots of the job I did if your interested in seeing exactly how much work is involved

[Guy]

The header in a concrete block wall is much different than a wood stud wall. Masonry that is above any opening has to be supported by a "Lintel Iron" (large angle iron) and reinforced concrete or masonry lintels (bond beams) or masonry arches. All of these need to be designed to support the imposed load. We use iron "I" beams when we need to insert a header at the top of a block wall. The wall needs to be jacked up on the inside so there's no sagging during the wall cut. The beam is set in place leaving a gap to the outside of the wall. Usually a six inch beam will leave a 1-1/2" gap to the outside to accept a cover block to match the wall. Mason's then install these after the beam is set in place. The inside is insulated and covered with a 1/2" plywood to flush the opening. The opening is usually cut 3" over the RO width & height so it can be bucked out with treated lumber. In any case it's a long hard road when doing it. Most installers will sub this out to a mason cutter to do. I know the going price here is around $3K per hole. So it adds up. Good Luck!!![/img]

[HoleInTheWall]

Thanks, PK & Guy.
I'd love to see any pictures you have of the process!

[PK]

http://www.patrickkubala.com/Images/sid ... %20018.jpg

http://www.patrickkubala.com/Images/sid ... %20019.jpg

http://www.patrickkubala.com/Images/sid ... %20025.jpg

I have some im progress ones somewhere no lintles were required on this job because all the block right up to the sill plate were knocked out this allowed us to simply frame with PT and use a properly sized header which had to be approved by an architect before we could pull permits

[HoleInTheWall]

Thanks, PK!