Decks, Patios, Porches and Docks - Free-standing patio cover

We currently have a concrete patio. To keep the weather elements away, I'm looking to get a solid patio cover. We live in Chicago area so the cover obviuosly needs to with stand the weight of snow/ice and also some heavy winds. We are talking about 12'X12' size of cover. My first preferece was to attach the back of the patio to the main structure of the house but the contractor is pushing me for "free standing". This way he can bypass city building code requirements and also it is lot easier to build since he doesn't need to dig and pour concrete for footings.

The way he is thinking is -
1) free standing structure
2) supported by 2 or 3 posts in the front
3) Two posts on the back (this will be close to the siding). There is no room for the 3rd post since there is a patio door in the way.
4) the bottom of the posts will be fastened to the existing concrete slab using concrete bolts (no digging or cutting of existing concrete)
5) he will use beams on top of posts and also joists to build the roof. He will build this as a normal roof.
6) he will connect posts and the beam using angles.
7) he will use shingles as roofing material

My question is - is this some thing that can withstand heavy winds and snow load? I am afraid it could collapse or blown away one day.

The contractor says the entire structure will be strong and sturdy because it is going to be heavy. Can we just rely on the self weight of the structure itself?

I appreciate your feed back.

I would probably put the beams between the posts creating a box, instead of on top and I would use 2 L brackets to connect it to the house. I would also pitch the roof slightly.

Thanks Pulpo!
Yes, there will be a pitch which I forgot to mention.

The thing about creating a box - I think you mean connect the posts using beams on the concrete slab. But this will create a tripping hazard though. I am sure it will give strength to the structure but having beams on the slab is undesirable.

I think your contractor is thinking absolutely backwards!

First (at least where I'm at), it makes no difference whether a patio cover is attached or free standing -- it HAS to have a permit. Check with your local bldg. dept. and see what they say.

Second, the engineering that I use for aluminum covers shows ALL free standing covers have posts that are embedded in footings, and those footings are larger than what is needed for the same size cover that is attached. Depending on the snow load, the spans involved and the number of posts I use, I can occasionally attach an attached cover directly to a slab without footings.

Third, weight isn't going to do anything to hold the cover in a wind storm. It'll just put more stress on the post to slab connections.

Thank you Lefty! I appreciate your feedback.

Zoning and building departments treat structures with permanent roofs differently from patios and decks.

If the structure is attached to the house has a permanent roof, it will probably be treated as an addition. If it is freestanding it will probably be treated as an "auxiliary structure". In either case construction usually requires a zoning analysis and a building permit.

A frequent problem for sellers when we are performing home inspections for buyers is that we find various kinds of auxiliary structures and additions which have been built over patios and decks without permits.

Usually, the unpermitted work will stand out because it is seldom done entirely to code.

In that case I'm legally obligated (by my responsibility to my clients, not because I want to play "zoning cop") to recommend the buyers perform a permit search on the property.

Often this in turn will turn up other unpermitted work such as kitchens and baths.

Typically, if the owners are cooperative, local building departments try to be accommodating and simply require that the work be brought up to existing standards. But sometimes - especially if the seller's are less than candid with the municipal inspectors - they can be pretty hard-nosed about it and require extensive changes or even demolition.

So IMO it's well worth spending the time and money to do what has to be done to ensure that your structure meets local requirements.

Michael Thomas,

A lot of what you said is true pretty much everywhere. But how bldg. and planning depts. treat decks, patio covers, patio rooms, and additions and how they define the differences between those various structures (and therefore what is required to construct one) varies from one jurisdiction to the next. And codes are always changing and getting updated as situations arise.

In a forum like this we can give people general guidelines, but the specifics of they will encounter at their local bldg. dept. (which is who has control over what they can and can't do, when a permit is needed, etc.) is a question that they can ONLY get the correct and final answer from their local bldg. dept.

I build decks, patio covers and patio rooms in 3 diffeent counties, and in 9 different cities within those 3 counties. Each has its own bldg. dept., and while the rules are similar, there are some specific differences between them all. That is 12 different interpretations of the same governing building code that I have to deal with and have to know the differences depending on where I'm working.

Agreed, that is why that post says "it will probably..."

and

"IMO it's well worth spending the time and money to do what has to be done to ensure that your structure meets local requirements."

I suppose that someone could argue that "likely" might have been more accurate than "probably", but the whole <i>point</i> of the post is that you need to make sure the structure <i>meets local requirements</i>, or there may be expensive and stressful complications later.

I bother to post this same message over and over because I am *very* tired of having to argue with builders, developers and sellers over unpermitted work: the bottom line is that my client (usually, but not always, the buyer) is potentially stuck with the cost of correcting it, negotiating how to apportion that responsibility is usually stressful and often expensive for at least one of the parties concerned, and people need to be aware up front of the potential grief such work often buys later.

So I really think we are on the same page on this one.