New concrete patio with lean-to roof on posts
evandelp
| Posted in Construction Techniques on
I’m building an 8×16 concrete patio with a lean-to roof over it. What is the proper way to ensure the slab and piers for the 6×6 posts interact properly? There will be three posts in the front of the patio. Dig and pour three piers for 6×6, pour patio on top of piers, and then attach posts to top of slab? Or pour piers to finished slab height and pour slab around piers?
Replies
Depends on where you are and the frost depth.
If you set the piers so they extend below the frost line, and the slab is not so isolated from frost heave, the interface will move.
That's correct, the piers will be below the frost line (pennsylvania)
If this is just a slab on ground without perimeter foundation walls, the one should always anticipate some amount of differential vertical movement over time. It's always better to have the top of the pier finished nice slightly about the slab.
Further, if your patio slab will wrap completely around the pier(s), one should install a compressible joint filler between the slab and the pier(s). This will help avoid slab cracking as the concrete shrinks during hardening.
For your patio project, it's best to pour the piers to the finished slab height and then pour the slab around them. This way, you ensure a solid connection between the slab and the posts.
Dig and pour the piers first, then pour the slab, making sure it's level with the tops of the piers. Once the slab is set, you can attach the 6x6 posts securely to the top of the slab. This method should give you a sturdy and well-integrated patio with a lean-to roof.
I trust you meant to say to attach the posts to the PIERS and NOT to the slab.
The slab will always move with frost effects but the piers will not. This is why I recommend constructing the piers a bit higher than the top of the slab.
To ensure the slab and piers interact properly for your 8x16 patio with a lean-to roof, here's what I'd recommend based on my experience:
Dig and Pour Piers: You should first dig and pour the piers below the frost line to ensure stability for the posts. Pour the piers to the finished slab height.
Pour the Slab Around the Piers: Once the piers are set, pour the slab around them. This method ensures that your posts are independent of the slab, so any potential movement of the slab (due to settling or shifting) won’t affect the posts or the roof structure.
Attach Posts: After the slab is cured, you can attach the posts to the piers using appropriate post brackets designed to secure 6x6 posts to the concrete piers.
This approach gives you the best structural integrity for the posts and roof while maintaining the patio's longevity. If you're looking for additional guidance on how to pour a slab, check out Hugo's Concrete for more expert advice.
https://hugosconcrete.com
Hugo,
I looked pretty hard for what you call “expert advice”.
Seems like the above is just a spam ad for Hugo.
No?
Pour piers to the finished slab height, then pour the slab around them for proper interaction.
Study up on control joints.
Avoid cracks around your piers.
Important to avoid the inevitable.
https://www.jlconline.com/how-to/foundations/joints-in-concrete-slabs_o
To ensure your patio is solid, pour the piers to the slab height and then pour the slab around them. This way, the posts are directly anchored into the piers, providing greater stability and better load transfer. Plus, it helps protect the posts from moisture. Afterward, use post bases to secure the 6x6s to the piers. It’s a robust approach that will keep your structure strong for years. Good luck with your build!