Enclosing underneath a deck to create garage

[KGorney]

Has anyone tried this or seen it done successfully?
I have a 12' by 24' deck off the first floor at the back of the house. Underneath is a walkout basement. I poured a concrete slab and retaining wall along the back short side and three quarters along the front. The slab is 4 inches in the middle, and 12 inches around the perimeter. So the foundation and framing is all there. I could easily add walls to enclose the area and basically have a one car stall to do work on my boat, small engines, snowmobiles, etc, freeing the space in my main garage.
I'm thinking of running 12 foot steel roof panels at a slight slope connected to the bottom of the ledger board extending out to the outer beam of the deck. Then install a gutter to catch the runoff and carry it away from the foundation.
I know there are under deck drainage systems you can buy, but the cost would be a few thousand for a deck my size and I don't want to put that much into what will basically be a shed.
Has anyone done this under a deck? Any suggestions?

 

[davidcalhoun]

My neighbor has a walkout lot and did a small 10 X 12 shed under his deck to hold his riding mower and garden stuff.

You are on the right track about creating a roof to control the water.

One thing to watch for. My neighbor forgot to put in some vents. He had a lot of mold growing on everything by spring.

PS also use treated 2 X for your sill on the concrete.

 

[1320stang]

What kind of vertical clearance do you have? You'll need to flash back under the siding on the house side and your roof panels will sit under that flashing flange.

 

[KGorney]

The height of the underside of the deck joists to the concrete pad is about 9.5 feet.
I would use 2x6 wall framing with a 2x6 pressure treated sill plate on the concrete.

The walkout basement does not open up to the inside of the house, as it is a second basement. After enclosing the deck I would open the separating exterior basement wall with a large doorway, in effect expanding the underdeck area into my woodstove heated workshop.

 

[kbs2244]

You are going to run into code problems. For sure if you open up the wall into a wood stove heated room. At the least you will need a 8 inch high fume stopper wall at the bottom of the door to step over.
Working on cars, with all their fumes, and wood stoves less that 18 inchs off the floor is real nono to the code guys. And, IMHO, for good reason.
You will mostlikely need a permit and a drawing to get approval since what you are doing is concidered a permenent inprovment.
One the other hand, if you just put the metal under the deck floor, hang some real heavy tarps, and use a small portable heater, then nothing is permenent and no permit needed.
How much car work do you do?

 

[KGorney]

I am in the process of having a separate garage for car work - I do a lot with older Mopars. It will be 26 x 24, 11 foot ceiling on the first floor, 8 foot ceiling on the second floor. It was the biggest I could fit in the most logical place on my 1 acre lot. I don't want to clutter it with my small engine toys and equipment.

The basement right now is where I have my woodworking shop for remodeling projects, etc. The enclosed deck outside will be for storing and working on lawnmowers, snowmobiles, etc.
There will already be a 4 inch step up into the basement due to the difference in height of the inside and outside slabs. In addition, the woodstove in 10 inches off the floor inside. Opening up the doorway would be well after the fact, in any case. Initially, I am more interested in getting under the deck weatherproof.

 

[boiler7904]

Where are you located? If snow loading is a factor, additional weight of metal roofing panels hanging below could put you over the allowable loading for the joists.

Call the local building department and talk to an inspector. See what their take is on this. My guess is that you'll have some hurdles to jump but it should be doable.

If I was you, I'd consider not leaving the garage area completely open to the woodshop. Use a fire rated steel door to get between the two spaces (like you would between a house and an attached garage). Technically, that should make you code compliant but if you happen to forget to close the door (wink,wink) while you're working in the space, the addition will get heated.

If the building department signs off, the most important thing is going to be detailing the connection of the panels to structure and the flashing at the house. Everything else is standard residential construction after that.

 

[KGorney]

Thanks for the replies. The steel door is a good idea.
I have run the rough plan by the town inspector and he said it would not be a problem. I am in NH, which historically has quite a snow season although you wouldn't know it the last few years.
I built the deck myself and went with 2x8 joists 12" on center as opposed to the code required 16" on center to increase capacity. I also overdid it on the 4x6 post spacing, which are all anchored to the concrete. Deep snow on top of the deck would be just as heavy, so I built it to handle a heavy load from the beginning. I plan to use galvanized steel panels which would conduct heat nicely and melt any snow build up that did occur.
I have thought most of it through. I'm no professional, but my house is a 2600 square foot farm house from the mid 1800's, that I have single handedly been remodeling for the last few years. The house is actually three square stuctures in a diagonal. I basically gut a room down to joists and then re-wire, plumb, insulate, floor, finish, etc. When ever I had questions or serious wiring or structural work, I always consult which ever contracting friend or relative is appropriate. (I am lucky enough to have a Master electrician as a brother in law, as well as freinds who are framers, HVAC technicians, plumbers, etc.)
However, the only part that worries me is installing the roof panels and making sure it will be leak proof, not promote rot or mold, etc. No one I talk too has done anything like it, but say the flashing, installation should still follow the basic principles of any roofing. (I have replaced two rooves on my house on my own). I can't seem to find anyone who has done it and can describe what worked to be problem free.
Again, thanks for all the suggestions thus far.

 

[boiler7904]

Can the deck boards be easily removed, saved, and replaced at a later date to facilitate installing the metal panels?

I can think of at least one way to do this if the decking can be removed.

 

[KGorney]

All of the deck boards or just along the ledger board?
Any of the deck boards could be removed as I fastened them with deck screws, which would be easy enough to back out. I wouldn't want to remove too many, or I'd be stuck with a giant jigsaw puzzle!

What did you have in mind?
Flashing down over the top of the ledger board, and a short distance out over the joists?

 

[1320stang]

One other thing I can think of, depending on debris and such that collects on the deck, will the metal roof tend to get dirty with twigs or dirt? Dirt would hold moisture, especially if there isn't much slope.

As far as supporting the metal panels, I'd probably support them from below. Which is why I aked about clearance.

 

[wrigh003]

One other thing I can think of, depending on debris and such that collects on the deck, will the metal roof tend to get dirty with twigs or dirt? Dirt would hold moisture, especially if there isn't much slope.

As far as supporting the metal panels, I'd probably support them from below. Which is why I aked about clearance.

My folks have a deck on back of their house with about a 15x25 slab underneath it. They paid some guy several years back to put up corrugated fiberglass panels, just to turn the water. Made a good place to put the lawnmower, tiller, whatever random stuff (nowadays LOTS of random stuff), etc. The bonehead didn't pitch it away from the house, though. :tard: Fortunately the structure down there is all brick, but still...

Come to think of it, that guy was the same one where I learned the "the contractor you hire to work on your house may or may not be a complete *****/ drug addict, get references and/or consider doing it yourself" lesson.

 

[kbs2244]

If the inspector is happy with your ideas, and it is built as strong as you say, and you have a "real shop" for the heavy work, then go for it. I am still not comfortable with open flames close to motor work. The house next door to my son isn't there anymore because of gasoline fumes from some motorcycle repair getting into the attached utility room with a gas hot water heater.

 

[KGorney]

I understand your point and open flames. There is/will be a 4 foot by 8 inch concrete wall between the basement and the underdeck structure or a length of about 10 feet. That will be between the area where the woodstove is located and the outer area.
In addition, the heating months are when I am in home remodeling mode full swing, so there will be little to no small engine work or even running during the times the woodstove is in use.

 

[Jeepster]

Check out the Zip-Up ceiling system Sounds like the perfect answer for what your trying to day

I have the Zip-Up Ceiling in my Garage, and I love it. Was incredible easy to install and looks great. It has a class "A" fire rating. From what I have read about RPVC in general, the don't burn easy and for sure do not contribute to a fire. This stuff is really tuff as well.

When I bought mine it was $2.20 sq ft. Put up 32 x 24 in under 6 hrs just me and one other guy. I have had it in my garage a little over 2 yrs and no problems here. The guys that sold it to me where very helpful too. Might be worth the look, especially if you plan on doing it your self.


http://www.zipupceiling.com

 

[KGorney]

Thanks for the link, Jeepster.
I don't know that I'd trust that system to hold up a load of snow and/or ice which could accumulate.
It does look worth considering for my new garage though!

 

[Jeepster]

NP KGorney, New to this journal thing and learning allot from all the inputs too. From review the web site again, I see they added deck pictures and as they are from MI I would guess they have experience with snow and loads & such. If you get a chance, phone calls are free pretty much anymore.

Kind of curious myself now. Look forward to seeing pictures of your finished project. I can see this kind of web surfing might get addicting Good luck either way!

 

[trovato]

Hello. Sorry to join this thread so late. I am in the process of doing basically this exact thing to my deck. I am using corrugated fiberglass panels instead of steel. They are attached using stainless hanger screws, so I can remove panels if major debris gets trapped above. This should also be handy when it's time to give the deck a stain/preservative treatment. These things are basically studs with a wood thread on one end and a machine thread on the other. I'm basically trying to use this space as dry storage, not workspace.

 

[trovato]

Look at www.mcmaster.com page 3113 to see what I mean. I'm using stainless nuts and washers as well.

 

[KGorney]

Thanks for the info, Trovato.
That's a good idea to make the panels removable in an easy fashion.

 

[Hades12]

Lowes or HD had a system to do just what you are saying, it was vinal and hung off the floor joists angled away from the house to a gutter at the end.

 

[trovato]

I looked into one of those and it was very expensive for a large deck.