Adding on to an existing building.

[AsSeenOnTV]

New guy. Off and on lurker. Love this forum.

We are about to close on our new place. (Dozen acre lot in suburbs, big house with attached 4 car and detached 40x60 (x12 at the edges shop) metal building. Insulated and open floor plan.


We want to extend each side of the shop, 14x60. On one side it would be a home gym with A/C and a bathroom. The other side would have 14x20 enclosed as a hobby room and the other 40x60 covered but open as a wash area/RV parking.

We would end up with a 68 x 60 shop.

Thoughts on the addition?

 

[matt_i]

Just a thought on adding to a stick frame building (tangentially applicable).

Match foundations type/style/depth so the building phases don't move relative to each other.

It requires very careful measurements if you want to extend a line of trusses, etc, so there's not a gap or dip or change in profile that will show in the rooflines, walls, etc. The red-iron metal building is unforgiving to field changes...

Depending on how long its been there, matching the colors, etc, is going to be nearly impossible....even if you can get exact manufacturer and color matches, the effect of weathering can't be compensated.

Having a drawing package from the OEM will help tremendously vs. having to reverse-engineer from "as-built" measurements.

 

[readhead]

Usually a metal building side addition is treated as a separate building attached to the existing building. None of the new addition shares components with the existing structure. Just about any building company can design an addition.

With that being said, what style of metal building do you have? Red iron or tube steel? The solution will be similar on each.

 

[AsSeenOnTV]

Usually a metal building side addition is treated as a separate building attached to the existing building. None of the new addition shares components with the existing structure. Just about any building company can design an addition.

With that being said, what style of metal building do you have? Red iron or tube steel? The solution will be similar on each.

Red iron.

 

[readhead]

Very simple process. You will end up with columns next to the existing building on new footings. Make sure to account for the inside and outside columns to determine the required inside width. Might want to request straight columns. Also make sure you have enough inside height with the new rafters. You will have less room by the time you get to the outside. Right now you have quite a bit less than 12' clear inside. There are ways to get around that.

 

[kbs2244]

The only problem is going to be roof pitch and outside wall height.

 

[Copymutt]

Trend in both residential and commercial seems to be contrasting facades. It would be easier to contrast w/ a complimentary color/ finish than any attempt to match it.

 

[WNYflyer]

Very simple process. You will end up with columns next to the existing building on new footings. Make sure to account for the inside and outside columns to determine the required inside width. Might want to request straight columns. Also make sure you have enough inside height with the new rafters. You will have less room by the time you get to the outside. Right now you have quite a bit less than 12' clear inside. There are ways to get around that.

Good advice. Many times I have specified straight columns with a minimum inside to inside dimension of face of columns/base plate and inside height to column/rafter joint to insure we are getting the required clearance for our needs. One potential problem with specifying the use of straight columns in the typical rigid frame structure is that it is not an efficient use of material thus an increased cost. Given the short span though I doubt there would be much, if any, cost penalty going with straight columns.

Getting your minimum vertical clearance inside the new building maybe a problem given you are constructing right up against an existing building but who knows. If you set minimum inside dimensions rather than out to out of building then there typically will be more back and forth with the building vendor to make sure the foundation and anchor bolt locations/dimension are coordinated with the building since you typically won't know the final column depths until relatively late in the game.

I would be interested in knowing if the OP has a handle on the type and dimensions of the foundation system of the existing building since that can have a big effect on the placement and design of the new foundations adjacent to the existing building and thus the placement of the new columns.

 

[AsSeenOnTV]

I would be interested in knowing if the OP has a handle on the type and dimensions of the foundation system of the existing building since that can have a big effect on the placement and design of the new foundations adjacent to the existing building and thus the placement of the new columns.

I dont. (We close in a few weeks on the place)

As a guess, the foundation probably does not extend past three sides (It is grass right up to the building) While unlikely, in the front, where there is driveway, I guess it could extend past the front wall, but that is not the direction I wish to expand in.

 

[pmiranda]

12' sidewalls on the existing building? what's the current roof pitch?
One nice thing with metal building add-ons is it looks normal (to me) if the "wings" are less pitch than the main structure. That helps cover up for any slight variation in pitch, panel pattern, or color you'll end up with at the transition between new and old.

 

[AsSeenOnTV]

12' sidewalls on the existing building? what's the current roof pitch?
One nice thing with metal building add-ons is it looks normal (to me) if the "wings" are less pitch than the main structure. That helps cover up for any slight variation in pitch, panel pattern, or color you'll end up with at the transition between new and old.

I dont know the answer but there is a (poor) picture above.

 

[pmiranda]

Counting pixels it's a 3/12. It won't have a ton of headroom, but enough to work in even if you did just follow the pitch.

 

[Joemctag]

What Miranda said. Min. slope for metal roof panels is still 1:12 I think. Would give about 12’-8” at eave (top of framing, underside of roof sheets), incl. new sheets starting say 2” lower than existing ones so flat flashing will work there. Don’t think you could properly slide one sheet under the other with that much difference of slope upper and lower roofs.So, 3:12 slope main bldg. flattening out to 1:12 at 14’ extensions. This is a commonly-seen thing. Wouldn’t look as good as, say, a 5:12 going to a 2:12 IMO, but would not look odd at all. Continuing out with the 3:12 slope all the way gives 8’-6” at new eave.With depth of framing members and insulation, it’ll give a low ceiling height. Also, if you need more height at the 14 x 40 RV bay, you could have them build you one of those square-tube carport-type buildings. You can get them in heavier grades, with engineering and everything where they’ll meet the code for an actual permitted building. Can get overhangs and as much of it closed in as you want. You pay more, but still the cheapest way to go . That slab should be lower so water doesn’t get in your main bldg. and 14 x 20. So the carport could be higher than the existing eaves: Leave the existing gutter on in that area. The square-tube bldg. people can actually give you fabricated lean-to structures for your 14’ wide extensions.I wish I’d known that myself when I stick built my extension onto an existing bldg. That route or stick-built would be a lot less than red iron, I’d think, but I can say that the people who they have draw up red iron bldgs., including additions like yours, are quite competent at it . That’s all they do and you should get a quality, commercial-grade bldg. The wall and roof sheets, for example, are far superior to ag. bldg. and carport stuff. Good luck and keep us informed. I’m from Texas myself and your picture makes me miss her.