Window installation, block wall ????

Danaus29 · #1 08/22/10, 03:35 PM

Ok, we need to replace a few windows in the guest house and don't know how to do this. The walls are concrete block with no framing, just the bare walls. How do we go about installing new windows? I do not want glass block in these openings, already did that in the bathroom. It's pretty and functional but not what I want in the rest of the house. The interior walls still need to be built so this is pretty much what would be considered new installation.

Thanks in advance.

||Downhome|| · #2 08/22/10, 04:00 PM

you need to frame in the rough opening and then install like in frame construction.

strawhouse · #3 08/22/10, 04:17 PM

Second on the framing in the opening, the only addition is put a barrier between the block and the wood framing. Usually we use a product like ice and snow shield but a product like tar papper could also work. It just allows the moisture that occcurs on the masonry side of things not to rot the wood framing.

ErinP · #4 08/22/10, 05:53 PM

You might also consider using pressure treated wood.

William G · #5 08/22/10, 06:09 PM

retro fit windows might be best they use the frame of the current window to install a new window we just replace our aluiminum frame windows with vinal windows

Danaus29 · #6 08/22/10, 06:40 PM

Would Tyvek (sp?) wrap work for a vapor barrier? I saw a display at a hardware/lumber yard for wrap that goes around window and door frames. Or could the wood just be painted or have linseed oil put on instead?

William G, there is no current frame. The old windows were metal framed crank windows, single pane. Once those were taken out there was no frame, just the concrete block.

Danaus29 · #7 08/22/10, 07:40 PM

Another quick question, would the framing need to be attached to the blocks? If so dh plans to use stainless Tapcon fasteners.

salmonslayer · #8 08/22/10, 07:56 PM

Quote:

Another quick question, would the framing need to be attached to the blocks? If so dh plans to use stainless Tapcon fasteners.

Yes Danaus, thats what we did with the windows in our concrete block garage and it worked great. We used Tyvek, attached the pressure treated framing wood with TAPCONs then installed the vinyl clad windows as normal. We ended up framing around the outside with the composit wood product (for the life of me I cant remember the name) and it really looks nice. A little caulking, some paint, and away you go.

Michael Kawalek · #9 08/22/10, 08:56 PM

HI Danaus
I'm planning on doing the same thing.

First, support for the blocks above. You'll need to look at a window table to decide what thickness of support wood that will span the opening. You select the size of window you want to place in the wall, then determine the size of the 2X? pieces that will support the blocks above. For small windows, 2X4's are OK. For a 4 foot wide window you'll need 2X6's.

Next, you'll need to shore up the ceiling joists so they'll bear the weight of the roof/ceiling when you cut open the wall. Lay a 2X6 on the floor, place at least two 4X4 posts standing up, and a second 2X6 on top of the posts against the bottoms of the ceiling joists. Wedge them in for a tight fit, which will take the weight off the wall at that position. You can also use custom ceiling jacks designed just for that purpose.

Now you are ready to cut the opening. What kind of saw will you use? You can use a rented gasoline saw you can rent at Home Depot. That will make up to a 4" kerf on one side of the wall only. Once you have cut the first kerf you go the the opposite side and do the second one. Hope very much that you have the two cuts perfectly aligned. If there is rebar in the middle, you will have to cut around it, then pound out the inner block later. Once the rebar is exposed you can cut through that will a cut-off saw. Once the opening has formed, you can take a chisel to make the surfaces completely even.

Now you are ready for the wood framing. You should make some light cement mix to trawl onto the cut blocks just before inserting the wood members. I'm going to anchor my wood with 1/4" concrete anchor bolts. I'll drill partway through the wood with a 3/4" bit, then all the way to the concrete with a 5/16" bit. Then drill with an impact hammer into concrete to drive in the bolts.

Once the wood framing is in place, your 4X4 support posts can be removed and the window and waterproofing installed just like any other window.
Good luck,
Michael

TnAndy · #10 08/23/10, 05:11 AM

Michael,

Good instructions on a wall with no holes, but since the OP said they are "replacing" windows, I take it there are existing windows with holes and support ( like a solid lintel ) already in place.

Danaus29:

You can frame in with wood if you want....I would use treated lumber, if you want a vapor barrier under the lumber ( which I wouldn't bother with under the block gets wet on a regular basis ), use tar paper. I am way UNDER impressed with Tyvek after removing siding on my house couple years ago and finding the Tyvek installed 20 years earlier had basically fallen apart.

You can also order vinyl replacement windows to the exact size ( and be sure to say EXACT size when ordering or they will cut them down ) of your opening ( less 1/4" ), then use Tapcon fasteners in the side jambs to secure the windows in the hole. You would then make an extension jam of wood inside from the window of 3-5" wide ( depending on where you set the window in the hole) to finish out the installation. Doing this, you can skip the wood around the opening, which would reduce your window size 3" height/width.

**Ross** · #11 08/23/10, 05:30 AM

Shims and tapcons work fine. Framing is just another thermal bridge. Then use low expansion foam. Your windows will need the casing extention to fit the wall. How are the interior walls being finished?

Danaus29 · #12 08/23/10, 02:22 PM

Holes are already in place. There were once windows in these spots. And several old single pane crank windows needing to be replaced.

TnAndy, that's what I was thinking could be done. Custom made windows to fit the current openings and just running Tapcons through where the nail holes are. Then frame up the inside just to pretty things up. i want the windows as close to the outer part of the wall as possible so I can use the inside for setting plants on the sills. The interior walls are to be done with 2 x 6's (overkill, I know. Have to run conduit and insulation on the exterior walls) and covered with panelling. I just wasn't quite sure how would be best to go about doing the windows. I plan on keeping all the moisture out that I possibly can. I had planned on filling the gaps with silicon caulk, as long as the gaps are small.

TnAndy · #13 08/23/10, 07:22 PM

Yep...you've got it.

Just to say again: be SURE you tell them EXACT SIZE opening, and give the width first and the height second.......or they will take your measurements as "opening size" and you will get windows that are cut down 1/2 to 3/4" width and height.

Measure the openings to the nearest 1/4" and that will give you 1/8" gap all around, easily caulked.

With 2x6 framing back inside the wall, your extension jambs are going to be DEEP. A vinyl replacement window is 3 1/4" deep.....assuming you have 8" block, that leaves you about 4 3/4" + 5 1/2" for the 2x6 + finish wall.....you'll end up with close to a foot of inside jamb/sill

Danaus29 · #14 08/25/10, 09:23 AM

TnAndy, yep. About a foot of interior window sill space. With a flourescent light at the top of the window they will become little mini greenhouses. Plenty of room and light for my orchids, amaryllis, ornamental peppers, and some herbs and catgrass. A little greenery is always appreciated during the long cold winter, especially if you can see some flowers too.