Building a chase questions?

[Michael Golden]

I am gonna be building a chase in a week and I have a few questions about materials and support. This chase will be covered in veneer stone so there will be a good bit of weight. Question One......I have seen where they hang all this weight off the side of the house, is this a good idea? Or should I dig in a couple tubes and make a footer to support some of this weight? Question Two......should I use treated lumber with marine grade plywood or would treated plywood be just fine? Question Three......should I cover the wood with house or tar paper before I put the metal mesh over it?

Thanks,
Mike

 

[webby3650]

If you are gonna cantilever the chase, you will need to be able to run floor joists into the envelope of the home and tie them into the rest of the structure. This is very difficult to add to an existing structure. This is typically done on new construction. If you can't do that, you will really need to dig down below the frost line and pour a footer, set a block wall and then build the chase ontop of that. Otherwise the chase and the house will expand and contract at different rates with each season.
You will want to use a piece of treated plywood fro the floor of the chase, the other framing can be construction grade lumber. I often see cantilevered chases with OSB floors, the OSB is just left uncovered on the bottom, exposed to the elements. It will only hold up for a few years like that.
You should put tar paper over the sheathing then put the lathe on over that.

I suppose if the tubes went very deep, beyond the frost line, it might be just fine. ?

 

[webby3650]

I just noticed your stove. Is the chase just for a 6" chimney? If so I would think the chase could be supported by the house with no problems. I assumed it was for a fireplace.

 

[Michael Golden]

Yes the chase is just going 6" double pipe. But, with the stone there will be quite a bit of weight won't there? I also thought about building a steel bracket almost like a air conditioner bracket and attach this into the poured walls of the basemen? Would this be a good idea?

 

[Michael Golden]

I guess I should say that this chase is gonna be pretty good size! It will be app. 5' x 2' x 20'......should be around 200 sq. ft. Of stone.

 

[webby3650]

Is it that wide just just for ascetics? It will look good, that's for sure. Being that big, I really think it should have it own footing though. The steel might work just fine, but it might not too.

 

[Michael Golden]

Is it that wide just just for ascetics? It will look good, that's for sure. Being that big, I really think it should have it own footing though. The steel might work just fine, but it might not too.

Yep just aesthetics! I think I may just go the steel route, I think 3 x 3 x1/4 angle will be strong enough along with tying it back in to the house. What do you think? I would go with the footing but with it being a newer house I don't know if everything is done settling, it has only been through one winter!

 

[fossil]

You need to be talking with a Professional Engineer about this. Or at least a Licensed Contractor. Rick

 

[Michael Golden]

You need to be talking with a Professional Engineer about this. Rick

You are probably right! But, my plan is just to over build it.....may even pour some concrete tubes just for ease of mind!

 

[infinitymike]

I assume it is cultured stone? It can average between 8-12 pounds per square foot so anywhere from 1600 lbs to 2400lbs.
Three steel brackets bolted to the foundation could probably hold it.
Use the brackets to hold a floor system made from 2x6's
Then build the walls on that. Attach the 2x4's on each side wall to the existing house and lag bolt it to the box beam of the first floor then the top plates of the wall, the second floor box beam and second floor top plates (if there is a second floor).
Then when you sheath the side walls nail it every four inches plus the lagged in 2x4 will help hang the framing as well.
You can use all regular framing materials but definitely need to put tar paper on before the lath.
I would build the floor system with a piece of painted plywood on the bottom then place that on the brackets and bolt it to the house box beam then put another piece of plywood on top and build the walls on that. Of course run the flue pipe before you sheath the walls.

 

[fossil]

And if it fails in any way, just contact infinitymike. He'll fix it all up for ya, I'm sure.

 

[infinitymike]

And if it fails in any way, just contact infinitymike. He'll fix it all up for ya, I'm sure.

If he builds like I suggested he'll only be contacting me to thank me

 

[pyroholic]

If you are gonna cantilever the chase, you will need to be able to run floor joists into the envelope of the home and tie them into the rest of the structure. This is very difficult to add to an existing structure. This is typically done on new construction. If you can't do that, you will really need to dig down below the frost line and pour a footer, set a block wall and then build the chase ontop of that. Otherwise the chase and the house will expand and contract at different rates with each season.
You will want to use a piece of treated plywood fro the floor of the chase, the other framing can be construction grade lumber. I often see cantilevered chases with OSB floors, the OSB is just left uncovered on the bottom, exposed to the elements. It will only hold up for a few years like that.
You should put tar paper over the sheathing then put the lathe on over that.

I suppose if the tubes went very deep, beyond the frost line, it might be just fine. ?

^^ This is the correct answer. Framing and remodeling houses is what I do for a living. Ideally something should be in the ground below frost line. Would it hold up without? Maybe.... Probably..., but maybe not. Build the chit out of it and hope for the best. Keep us posted, with pics.

 

[ironpony]

O.K I am going to help out a fellow Buckeye. I am a licensed contractor, first off you are not going to attempt to "hang" 2400 lbs off the side of your house. You are going to do it correctly. After you locate where the chase is going to be, first is to remove the band board in that section , revealing the tails of the floor joists. Then you are going to size the joists to match existing. To frame a cantilever, for each one foot of cant you MUST have 3 feet of joist under the house, so for 2 feet of cant you will have 6 feet under the house, 8 foot joist. You will sister these to all the joists exposed and each outside rim will go under the house and be attached to a header between the 2 end floor joists. this will create a platform to build the chase on. From here up will be standard framing practice. You will tar paper before applying lath and scratch coat for attaching stone.

 

[ironpony]

And if it fails in any way, just contact infinitymike. He'll fix it all up for ya, I'm sure.

have to agree

 

[ironpony]

I assume it is cultured stone? It can average between 8-12 pounds per square foot so anywhere from 1600 lbs to 2400lbs.
Three steel brackets bolted to the foundation could probably hold it.
Use the brackets to hold a floor system made from 2x6's
Then build the walls on that. Attach the 2x4's on each side wall to the existing house and lag bolt it to the box beam of the first floor then the top plates of the wall, the second floor box beam and second floor top plates (if there is a second floor).
Then when you sheath the side walls nail it every four inches plus the lagged in 2x4 will help hang the framing as well.
You can use all regular framing materials but definitely need to put tar paper on before the lath.
I would build the floor system with a piece of painted plywood on the bottom then place that on the brackets and bolt it to the house box beam then put another piece of plywood on top and build the walls on that. Of course run the flue pipe before you sheath the walls.

not very convincing..........................

 

[Michael Golden]

O.K I am going to help out a fellow Buckeye. I am a licensed contractor, first off you are not going to attempt to "hang" 2400 lbs off the side of your house. You are going to do it correctly. After you locate where the chase is going to be, first is to remove the band board in that section , revealing the tails of the floor joists. Then you are going to size the joists to match existing. To frame a cantilever, for each one foot of cant you MUST have 3 feet of joist under the house, so for 2 feet of cant you will have 6 feet under the house, 8 foot joist. You will sister these to all the joists exposed and each outside rim will go under the house and be attached to a header between the 2 end floor joists. this will create a platform to build the chase on. From here up will be standard framing practice. You will tar paper before applying lath and scratch coat for attaching stone.

What if my floor joists run perpendicular to my future chimney?

 

[fossil]

You'll need to rotate your house 90°.

 

[Michael Golden]

Should re-word that, the joists run parallel with the wall the chase will be built on!

 

[Michael Golden]

Didn't plan on the chase thing, but the wife wants that pipe hidden!

 

[webby3650]

Didn't plan on the chase thing, but the wife wants that pipe hidden!

To have it done properly, expect to spend between $8-$10K. Does she mind the look of that pipe that much?

 

[Michael Golden]

Well I don't plan on spending that type of money! But I have been given two ways to go with this, and I'm guessing they both think there way is the proper way. This is why I love this site because there are many knowledgable people here. I will post some pictures once I get going on this project.

 

[infinitymike]

What if my floor joists run perpendicular to my future chimney?

C'mon iron pony, now what?

 

[ironpony]

Should re-word that, the joists run parallel with the wall the chase will be built on!

well reframing the floor joists and adding the necessary structure is probably beyond the average DIY project.
Your best option would be to dig down 36 inches and pour a footer then lay block back up to your foundation height.
frame new floor joists and build on top of that.

 

[infinitymike]

I've been a framing contractor for 29 years. I've been framing 4000-15000 square foot homes for 25 of those years.
I've seen many new homes where the foundation was so out of square there wasn't enough of the brick shelf left.
The mason contractor would bolt a 4"x4"x3/8" angle iron the length of the wall and support two stories of real brick.
3 brackets welded in triangles, made from 4x4x3/8 angle and bolted with 5/8" rod drilled all the way through the foundation wall with a 4x4 plate on the inside of the basement will hold up a more then 2400 lbs. now I only say that if its a poured foundation. If its block forget it.

Then there are two options. Double up a floor joist about 4 feet back from the wall. Build 4 temporary support walls under the floor joists.
Cut out a 3.25" chunk out of the flor joists where you will then put a header that will cantilever out the 2'
Teco all the joists and frame the chase.

Or put two 10" sono tubes in the ground 3' and out of the ground a few inches. Set an anchor bolt to attach a Simpson Post base bracket. Install a 4x4 post level with the top of the foundation and put your header on that. Lag a ledger joist to the house box and frame your 19.5 inch floor joists from the ledger beam out to the header.
Plywood the deck, frame the walls, bla bla bla.