Mounting a new pergola

Hi experts,

my wife wants me to out a spa on an existing slab in the yard. How would you mount a pergola to it? I want to cover the spa from sun/rain

do i cut out squares in it and repour to secure metal strapping?

 

I remember looking at a process similar to bolting the roofs of underground mine where a hole was drilled and a bolt with epoxy was spun into the hole. We looked at this process for bolting RR rails to concrete bridge decks. Something like that may be available for your use.

 

I used these. Look great and they keep the post off of the ground to avoid insects and water. Shop around you can get them for less. This was the 1st place i saw them. Whatever you use you need to make sure the slab is thick enough.

 

I would drill for anchors and use metal brackets given the slab is rated for the weight and anchors.

 

Do you know the slab is adequate? Footing design if any, PSI rating of concrete, thickness, reinforcement type and size? You don't want to spend on anchoring to a slab that might crumble once substantial weight is placed on it. If you have space and it might be somewhat temporary, I have cut plastic 55 gal barrels with a nice decorative edge at about 1/3 height, drilled a few drain holes and piped the drain up about 10" then formed a 5" higher post base in the center with a section of 5 gal bucket about 5" from the top of the barrel. Finally poured concrete in to create a free standing anchor with an elevated post base in the middle and potting soil around it. The finished product is a nice, long lasting, very heavy, huge decorative flower pot with drains and a free standing pergola anchor. You can buy the galvanized post base made by Simpson Strong Tie or similar, put a couple of bolts in the holes to let it "grab" even better in the concrete. Plant with anything you choose to accent your space. Don't forget the outdoor speakers and mini fridge!

 

The slab is 4-6 inches thick, dont quite remember, it was poured by a concrete guy 8-9 years ago so I don’t remember the exact specs on it. Thats why i was almost thinking i may need to cut sections out and make sure the footing are deep enough to hold it down in the wind

 

Would not cost much to place a trashcan on one corner and fill it with water to test the integrity for a couple of days before you proceed. If good just rent a hammer drill and buy some post bases. Drill the holes deep, at various angles. Then blow out dust with compressed air. Get one of those cylindrical shaped brushes on a long twisted wire handle and run it in the holes with a drill to clean away loose material and dust while blowing air. After all clean and dry use concrete anchoring epoxy to place your anchors. If they are put in at angles in various directions, wind shouldn't be a problem. Be careful with the hammer drill in case it gets caught on rebar, you don't want a broken wrist so just go slow and steady with it. It should pretty much drill like hot butter though. Drill with a bit about 1/4" or so larger than your anchor dia.

 

Your concrete guy may have a recommendation. If he says it’s good to go, I wouldn’t create more work. Building codes should have mandated the standards he used back then.

 

thats my concern. The guy we used I wouldn’t trust following building codes

 

No building codes or inspections on exterior slabs.

 

If it's a pre-fab pergola with a metal roof those are pretty light and would not require footings. I would just drill and use a retro-fit anchor, either the expanding wedge type or epoxy type. A lot of people just set them on the slab and wait for a storm to blow them away, so props to you for anchoring it down LOL

I recently built a patio and I built the roof to match the house, so I used 6x6 posts, LVL beams, 2x6 rafters 16" on center, plywood, and shingles. This was considerably heavier and required footings to be poured. Good luck with your project!

 

What he said,

 

A vynil framed pergola could work. I am gonna price out vynil vs wood. If i do a roof over it ill do a simple sheet metal, the modern looking style