Do I need stud walls for my small lean-to bump-out?

[rambleonrose]

So I'm doing a small lean-to addition to my garage. It'll be 6'x14', slab is already poured (4" thick), and the idea is to have a place to park 1-2 motorcycles. I'll have a shed door facing the alleyway, and will cut out a man-door-sized opening into the main garage.

My question is: do I need to build full stud walls? I was planning to just build it like a lean-to carport, with 3 4x4 or 6x6 posts anchored to the slab along the outer edge and a header screwed into the existing garage. I'll then just add enough horizontal framing in between to attach the siding (Home Depot engineered cedar-look to match garage). I'm assuming this will be enough support, and will save the cost and trouble of doing proper stud framing. I am in Denver. Do I need to worry about wind-load? I assume snow-load isn't an issue since people build full carports this way. Will I regret not having the studs for interior attachment points? Is there something else I'm overlooking?

Attached are pictures of the rough plans, drawn up to include the full framing, as well as a picture of the space:

 

[rancherbill]

My question is: do I need to build full stud walls? I was planning to just build it like a lean-to carport, with 3 4x4 or 6x6 posts anchored to the slab along the outer edge and a header screwed into the existing garage. I'll then just add enough horizontal framing in between to attach the siding (Home Depot engineered cedar-look to match garage). I'm assuming this will be enough support, and will save the cost and trouble of doing proper stud framing. I am in Denver. Do I need to worry about wind-load? I assume snow-load isn't an issue since people build full carports this way. Will I regret not having the studs for interior attachment points? Is there something else I'm overlooking?

I'd say you should. The HD stuff needs support. Wind, rain, snow are enemies of flimsily installed siding. If you sell people will see it as a crappy afterthought vs. a quality space addition.

 

[jack stand]

Is your slab level in the 14' dimension?
I'm with rancherbill on the stud wall, although if you're slab isn't level this will add complexity to your build assuming that you're not very familiar with framing.
You'll need purlins on your rafters to support and attach the polycarbonate panels to
A stud wall will eliminate the (drawn) beam and the 6x6 posts probably making it a "wash" with material costs but give you better results using a standard 2x4 wall.

 

[Copymutt]

Needed a structure to keep my plow truck out of the elements. Similar attached carport type design. From previous experience w/ ag building I sourced custom cut UV impervious tarp panels from Farmtek for the walls. Roof is metal on purlins. These panels are 8 yrs old now. Even w/ severe sun & winters they still look great. Only need 3 4x4 post on the 16’ side.

Home - FarmTek - Hydroponic Fodder Systems, Farming & Growing Supplies, Hoop Barns, Poultry & Livestock Equipment, High Tunnels, Greenhouses & More

FarmTek offers the best customer service and most economical prices on products for the agricultural industry. Product offerings include farm supplies, aquaponic, poultry supplies, agriculture products, animal housing, home improvement, commercial high tunnels and hoop houses, fodder growing...

www.farmtek.com

 

[CraigStu]

I'd build a standard 2x4 stud wall. Not sure how many friends you can get to help move it so consider doing two 7ft sections. Overlap the top plate and add one extra stud to one of them so your 8ft wide (two 4ft panels) engineered cedar overlaps the joint. BTW, you are really close to the ground so consider some kind of extra moisture shielding for the bottom of the siding. At minimum 3 coats of waterproof paint on the edge and a foot up inside and outside.

 

[Hank11]

Stud walls will be easier, faster, more supportive of your sheathing and probably cheaper.

 

[Old Moparz]

You might also consider framing the walls in a similar way that pole barn walls are built. Once your vertical posts are set & the roof framing is finished, the walls can have horizontal 2x4's.

 

[rambleonrose]

Thanks for all the replies! I'll try to respond to everyone here specifically, but in general it seems like people are steering me towards stud walls without corner posts. Seems like it'll be cheaper, and feel more premium in the end as opposed to pole barn style?

I'd say you should. The HD stuff needs support. Wind, rain, snow are enemies of flimsily installed siding. If you sell people will see it as a crappy afterthought vs. a quality space addition.

That's a good point. What I meant by "horizontal framing" is exactly what @Old Moparz described below. Do you think it'd still be seen as an afterthought if it's "proper" pole barn construction?

Is your slab level in the 14' dimension?
I'm with rancherbill on the stud wall, although if you're slab isn't level this will add complexity to your build assuming that you're not very familiar with framing.
You'll need purlins on your rafters to support and attach the polycarbonate panels to
A stud wall will eliminate the (drawn) beam and the 6x6 posts probably making it a "wash" with material costs but give you better results using a standard 2x4 wall.

Yeah it's level both ways. Thanks for the note on the purlins, totally makes sense. I would've gotten to that point and scratched my head for a while, thanks for the heads up!

Needed a structure to keep my plow truck out of the elements. Similar attached carport type design. From previous experience w/ ag building I sourced custom cut UV impervious tarp panels from Farmtek for the walls. Roof is metal on purlins. These panels are 8 yrs old now. Even w/ severe sun & winters they still look great. Only need 3 4x4 post on the 16’ side.

Home - FarmTek - Hydroponic Fodder Systems, Farming & Growing Supplies, Hoop Barns, Poultry & Livestock Equipment, High Tunnels, Greenhouses & More

FarmTek offers the best customer service and most economical prices on products for the agricultural industry. Product offerings include farm supplies, aquaponic, poultry supplies, agriculture products, animal housing, home improvement, commercial high tunnels and hoop houses, fodder growing...

www.farmtek.com

That sounds like a great solution! I think in my case I want to use the siding that matches the existing garage so it looks more cohesive. Thanks for the note on post sizing, I was going to go 6x6 just "to be sure" but don't want to do anything unnecessary...

I'd build a standard 2x4 stud wall. Not sure how many friends you can get to help move it so consider doing two 7ft sections. Overlap the top plate and add one extra stud to one of them so your 8ft wide (two 4ft panels) engineered cedar overlaps the joint. BTW, you are really close to the ground so consider some kind of extra moisture shielding for the bottom of the siding. At minimum 3 coats of waterproof paint on the edge and a foot up inside and outside.

Great points, totally makes sense. Is overlapping the way to do it as opposed to butting and running some sort of sealant bead?

I intentionally poured it to be level with the floor of the existing garage in case I want to fully open it up to one big space in the future. I'll be sure to think about extra moisture shielding.

Stud walls will be easier, faster, more supportive of your sheathing and probably cheaper.

Are they indeed easier and faster? I'm green to framing (obviously...) and the perceived simplicity is what was leaning me towards the pole barn style.

You might also consider framing the walls in a similar way that pole barn walls are built. Once your vertical posts are set & the roof framing is finished, the walls can have horizontal 2x4's.

Thanks for sharing that picture, that is exactly what I meant by "horizontal framing" for siding attachment. Do you feel that's a better approach for what I'm doing, as opposed to just stud walls? One reason I was leaning toward the pole barn approach is that I could break it into chunks and put up a carport one weekend, then enclose it another.

 

[captain14]

Post up your build and photos as you go along. I’m interested In Seeing the finished bump out garage.

 

[LOW1]

Do you have building codes to follow?

 

[driftpin]

What is your permitted setback? I suspect your prospective addition won't meet your local zoning code for property setback.

If you post your municipality then someone can tell you where to find your local ordinances to such info. The Building Dept. website will have links to your adopted ordinances for setbacks and building requirements. Save yourself the pain of having to demolish an unpermitted building.

 

[Old Moparz]

Thanks for sharing that picture, that is exactly what I meant by "horizontal framing" for siding attachment. Do you feel that's a better approach for what I'm doing, as opposed to just stud walls? One reason I was leaning toward the pole barn approach is that I could break it into chunks and put up a carport one weekend, then enclose it another.

I wouldn't say it's better, just that it's an alternative & may have advantages in your situation. I like that the only framing that will be close to the slab is the pressure treated splash board. If you went with conventional framing every stud will be just a few inches away from the slab.

Your slab is at grade (ground level) so the wall will be more susceptible to moisture & insects. I repaired my mother in law's ranch house on a slab & had never seen so much water & termite damage in my life. I replaced the entire front & left side walls of the house, about 60 feet of it.

And yes, you can frame the carport type structure first, roof it & do the walls whenever.

 

[NUTTSGT]

Me ? I would lay a course of block & frame a stud wall atop of it.

What you're doing is almost exactly what I did in my Garage Refurb thread.

I think it starts here.

Post in thread 'Garage Refurb®' https://www.garagejournal.com/forum/threads/garage-refurb-r.75024/post-2261010

 

[rambleonrose]

Do you have building codes to follow?

Nope, it’s under 200 sq ft and 8 ft tall which does not require a building permit

 

[rambleonrose]

What is your permitted setback? I suspect your prospective addition won't meet your local zoning code for property setback.

If you post your municipality then someone can tell you where to find your local ordinances to such info. The Building Dept. website will have links to your adopted ordinances for setbacks and building requirements. Save yourself the pain of having to demolish an unpermitted building.

I appreciate that. Because I’m in a fairly dense area the property side setback is 0’. And it doesn’t extend past the garage which already meets the alleyway setback requirement

 

[Hank11]

A skirtboard would help to make it last longer. Although fairly dry where you are you do have some real snow there. It'd be nice to keep any non waterproof materials up off the ground.

On the other hand, your garage seems to be OK without a skirtboard.

As far as framing goes, you could go in the garage and look at what the builder did there and copy it. If it seems baffling, come back here for comment.

Finally, you could build this whole thing out of 2x4s. (Or 2x6 for rafters if you want super stout). No need for anything heavier given the short spans you have. Pressure treated for the bottom plate and standard framing lumber for the rest. Biggest challenge will be the door opening. Pay attention to how that's done.

 

[BombShelter]

I'm no expert but I think the code is for the total sq/ft including garage, not just the addition. People are always improperly adding to their garages but if they don't do it to code it always looks like it's falling apart after a few years.

The big red flag I see is no footing or thickened edge. I think large posts are fine (and then put siding on) but code most likely would require a footing, personally I'd look into Diamond Piers (Home Depot). When I see lean-tos, the posts are outside of the concrete pad, it looks like your space is limited. Up here the setback is usually 3' or 1', normally it's the roof overhang since it gets closer to the property line than the concrete.

 

[rambleonrose]

A skirtboard would help to make it last longer. Although fairly dry where you are you do have some real snow there. It'd be nice to keep any non waterproof materials up off the ground.

On the other hand, your garage seems to be OK without a skirtboard.

As far as framing goes, you could go in the garage and look at what the builder did there and copy it. If it seems baffling, come back here for comment.

Finally, you could build this whole thing out of 2x4s. (Or 2x6 for rafters if you want super stout). No need for anything heavier given the short spans you have. Pressure treated for the bottom plate and standard framing lumber for the rest. Biggest challenge will be the door opening. Pay attention to how that's done.

Yeah, I'll probably do a PT skirt/splash board either way. The bottom of the garage siding is starting to get a little soft...

To be honest, getting the door opening right is part of what has me leaning towards the pole barn style construction, since that way the posts are holding up the weight and I don't have to get that framing exactly right. Also, it leaves the option to add a yard-facing man-door or a window later on if the alley-door and garage-interior opening aren't enough, as opposed to having to get it all correctly planned from the beginning.

 

[rambleonrose]

I'm no expert but I think the code is for the total sq/ft including garage, not just the addition. People are always improperly adding to their garages but if they don't do it to code it always looks like it's falling apart after a few years.

The big red flag I see is no footing or thickened edge. I think large posts are fine (and then put siding on) but code most likely would require a footing, personally I'd look into Diamond Piers (Home Depot). When I see lean-tos, the posts are outside of the concrete pad, it looks like your space is limited. Up here the setback is usually 3' or 1', normally it's the roof overhang since it gets closer to the property line than the concrete.

Right, the code for the garage was already met when it was built. This is effectively just a shed next to it, which should fall under the <200sqft part of the code.

The garage is on a floating slab without thickened edges (Denver has 36" frost depth), which is why I had this poured as a floating slab as well without any sort of footing/pier. As I posted above the setback for my zoning is 0' as long as that is not the gable-side.

My plan was to use post anchors (like this) to set the posts on the concrete, because I want the garage and lean-to to move together with frost heave.

 

[LOW1]

Right, the code for the garage was already met when it was built. This is effectively just a shed next to it, which should fall under the <200sqft part of the code.

The garage is on a floating slab without thickened edges (Denver has 36" frost depth), which is why I had this poured as a floating slab as well without any sort of footing/pier. As I posted above the setback for my zoning is 0' as long as that is not the gable-side.

My plan was to use post anchors (like this) to set the posts on the concrete, because I want the garage and lean-to to move together with frost heave.

Before I started I would email the building official and get his/her written agreement that an addition to a garage does not require a permit.

The concern is that if you build one 200 foot addition and then another 200 foot addition and then another sooner or later you are going to end up with a shop that GJ members will envy but your neighbors will hate.

And in some places if the building official gives you bad advice you may still have to tear it down if it violates code. So be careful.

 

[rambleonrose]

Before I started I would email the building official and get his/her written agreement that an addition to a garage does not require a permit.

The concern is that if you build one 200 foot addition and then another 200 foot addition and then another sooner or later you are going to end up with a shop that GJ members will envy but your neighbors will hate.

And in some places if the building official gives you bad advice you may still have to tear it down if it violates code. So be careful.

Totally, I appreciate the caution.

The zoning permit application was submitted a while back and I actually just heard back an hour ago that it is in their "walk-through review" process, which is their fast-track permit process, and I should hear back within 1-2 weeks.

 

[rancherbill]

Thanks for all the replies! I'll try to respond to everyone here specifically, but in general it seems like people are steering me towards stud walls without corner posts. Seems like it'll be cheaper, and feel more premium in the end as opposed to pole barn style?


That's a good point. What I meant by "horizontal framing" is exactly what @Old Moparz described below. Do you think it'd still be seen as an afterthought if it's "proper" pole barn construction?

Horizontal framing will not work with siding. Siding is long boards that are perhaps 16' long and 6-10" wide. Unless you are putting them vertically there is nothing to nail them.

 

[Firebrick43]

Horizontal framing will not work with siding. Siding is long boards that are perhaps 16' long and 6-10" wide. Unless you are putting them vertically there is nothing to nail them.

Did you look at the pictures? Its T111. Of course it will work with horizontal girts.

 

[Bert_]

I built a little 8x12 portable shed a while back. Not exactly the same, I didn't do any concrete and just put tin on the outside. I used a minimum amount of material to build it.

Nice thing is I can easily move it or sell it if I want something different. I'm thinking of building a ~12x20 the same way

 

[CraigStu]

If the siding on your garage is getting a little soft at the bottom, think about a fix for that too. That way whatever you come up with you can do the shed now and garage later so they match. There are a lot of ways to do it but one that is readily available is whatever your store has as in stock inexpensive Trex type deck boards. Be sure to get the ones w/o the groove in the edge. Lay the 1x6 trex on the concrete and nail or screw to your wall framing. Cut the siding 6 inches short, run an oversized bead of exterior sealer on the top of the 1x6 and drop the siding into it. Sometimes it is easier to wipe the squeeze out off right away and sometimes it is easier to let it harden and cut off w/ a utility knife. W/ the info that there are no footers or thickened edge, in my mind that really makes the standard 2x4 wall the better idea. That way the load is spread evenly along the concrete vs being concentrated at each post.

 

[captain14]

Consider “Z” flashing between the T-111 and the new section of wood when you cut out the soft wood at the bottom.

Do not leave items against the siding so it remain wet and damp.

 

[rambleonrose]

If the siding on your garage is getting a little soft at the bottom, think about a fix for that too. That way whatever you come up with you can do the shed now and garage later so they match. There are a lot of ways to do it but one that is readily available is whatever your store has as in stock inexpensive Trex type deck boards. Be sure to get the ones w/o the groove in the edge. Lay the 1x6 trex on the concrete and nail or screw to your wall framing. Cut the siding 6 inches short, run an oversized bead of exterior sealer on the top of the 1x6 and drop the siding into it. Sometimes it is easier to wipe the squeeze out off right away and sometimes it is easier to let it harden and cut off w/ a utility knife. W/ the info that there are no footers or thickened edge, in my mind that really makes the standard 2x4 wall the better idea. That way the load is spread evenly along the concrete vs being concentrated at each post.

Thanks for the Trex tip.

That's a great point on the 2x4 wall with the proposed posts being so close to the non-thickened edge...

 

[rancherbill]

Did you look at the pictures? Its T111. Of course it will work with horizontal girts.

You're right it is not the horizontal siding I was thinking about.

 

[rambleonrose]

Thanks for all the input everyone! Shed is almost complete and I've started a thread to document it in the gallery: https://www.garagejournal.com/forum/threads/bmw-motorrad-shed.528084/