Walls and Ceilings - New wall attachment to existing concrete block wall

Hello, and I thank you now for your help, advice, and experience...

We have purchased a 1960's built school which has cement block walls on the inside, with brick on the outside. We want to sub-divide the gymnasium. What is the best way to attach new walls (which would run perpendicular to the existing cement block walls)? (We do not want to cover the existing walls, but attach new walls at 90 degrees from them).The floor is concrete, all above grade. All is in excellent condition. Thanks.

Let me ask you this: How are the insides of the concrete wall getting finished? The reason I ask, is you may be overly concerned about how to attach the perpendicular wall when you really don't have to be.

If your new perpendicular wall will butt to outside framed walls, then common framing joinery will be used (called an "inside corner") and there really is no need to even attach it to the block wall!

Also keep in mind that you will be anchored at the floor and ceiling. The wall is not going to be going anywhere. It
is simply a matter of attaching it, primarily in the middle, so it doesn't bow and cause cracking of say the sheetrock tape in the corner.

The quick and easy way is to rent one of those 22 cal. "pistols" that uses color coded shot charges to fire a concrete nail into the cement. These work great on the solid concrete floor and will work on the walls to. One person may choose to shoot it into the mortar joint out of fear of causing the block to fracture. Where they rent these guns at any rental store, I'm sure the person on duty can school you on the best technique and what nail length is best. You do not need a lot of penetration.

[You can actually use these guns to fire nails clean into steel forms (like "maxiforms") at big construction jobsites. That is how powerful and quick the nail speed is. Sort of like how tornados can fire straw into telephone poles and wood through the sides of cars, etc.]

If the bottom plate 2 x 4 is shot to the concrete floor and the top is secured and you apply a wavy bead of Pl-200-like adhesive between the 2 x 4 and cement wall, and shoot some nails in there, that wall ain't going anywhere.

The high speed travel from the gun-fired nail will cause less damage to the concrete or mortar than will hand nailing with concrete nails.

It used to be (its' been about 20 years since I have used one) that the red charge (gunpowder) was the most powerful charge and that stringer of charges was used to shoot 2 x 4's into solid concrete or solid steel, as mentioned. The yellow and green? are less powerful.

You have to use lesser powerful charges when going into concrete block or mortar. Even if you do not get full depth penetration where the nail head is still sticking out of the 2 x 4 some, that will not hurt anything. Nobody will see that. Here is the theory: Let's say you only got 1/4 inch penetration into the cement or concrete. Once the wall is framed up and rocked or whatever, the 2 x 4 will no longer be able to come inward, away from the block wall. That 1/4 inch penetration will still lock that 2 x 4 enough that you can't push or pull sideways, on that 2 x 4. And the PL-200-like adhesive is added insurance.

After reading both posts, I had to chime in. Being a gymnasium, will you be using the entire height, or will there be a stopping point where the walls will be ceiled? If you don't use the entire height, you may want to consider using Tapcons on the wall studs where they intersect the block wall.

The obvious questio -

1. What are you planning on using for the interior walls?

2. What is the proposed use for the space?

Having a brick "schol sized" building, I assume someone will ask for a permit along the line unless you have already gotten one. If not get a professional to help you get the most out of it in terms of use and level of construction.

Chopping up a gym with high walls obviously leads to some big HVAC problems in addition to exit and fire requirements.

If you help attaching a wall, you probably need assistance in other areas.

Dick

Hello, and I thank you now for your help, advice, and experience...

We have purchased a 1960's built school which has cement block walls on the inside, with brick on the outside. We want to sub-divide the gymnasium. What is the best way to attach new walls (which would run perpendicular to the existing cement block walls)? (We do not want to cover the existing walls, but attach new walls at 90 degrees from them).The floor is concrete, all above grade. All is in excellent condition. Thanks.


Thanks for the help. To answer a few of the questions posed to me...

ecman51's-The existing inside walls are cement bock, and are painted. The new walls will be standard 2x4 or 2x6 wooden frame, with electrical installed, insulation, vapor barrier, and drywall.
The outside walls are not framed, they are cement block.

chandler-The walls will not go the 19' to the existing ceiling, but will stop at 10' and a an insulated ceiling will be installed.

concretemasonary-This is an actual school building, not just school sized.
There are no permits required here. Really. Niobrara County, Eastern Wyoming.
No HVAC is installed, nor will it be. The spaces will be an office and a dining room, with the remainder of the gymnasium/auditorium untouched.

To all, thanks. My major concern in using .22's or Tapcons is whether they would break the cement block.

Tapcon are the way to go. Tapcon screws will not damage your block or break if they are installed correctly and the right size screw is used. Thereis a installation video on
www.confast.com.





QUOTE=Trell;1270248]Hello, and I thank you now for your help, advice, and experience...

We have purchased a 1960's built school which has cement block walls on the inside, with brick on the outside. We want to sub-divide the gymnasium. What is the best way to attach new walls (which would run perpendicular to the existing cement block walls)? (We do not want to cover the existing walls, but attach new walls at 90 degrees from them).The floor is concrete, all above grade. All is in excellent condition. Thanks.[/QUOTE]

A thousand thanks!! Great video.