I need to install 4" x 4" posts onto an existing cement patio. How do you anchor them?

Question

I will be installing a railing so the posts must be secure.

Answer 1

You can buy U shaped metal brackets that you bolt to your cement with cement anchors then you bolt your 4 X 4 post to them.

They are very solid. Ours have been in for many years. It you anchor them correctly into your existing deck then tie then together with your cross pieces.

Ask at your local home improvement store. It will save you a lot of work and expense and I can testify if correctly installed are solid as a rock.

Answer 2

I am just answering this so that you know you do have 2 options if the top of the 4x4 post is also going to be anchored to something then the steel post anchor will work but if it isn't then yes the more of the post that is below the concrete pad the stronger it will be

Answer 3

Digging out and repouring will be more secure, however the problem with that is it increases the chance of rot and degradation of the 4x4 that is below the level of the concrete. The most ideal is to dig up the area, pour new concrete, sink a bracket (two U's offset 90 degrees from each other, they have a ton at your local hardware store) into the concrete, then attach the 4x4 to that. cokefreak's idea works well, but you would want to use epoxy to secure the bolt, not concrete, as concrete wouldn't be anywhere near as strong, and harder to work with

Answer 4

I guess you have the patio ready? My advice is to go to Lowe's/home depot and by some anchors, they should be like a "u" frame metal with a bolt on the opposite side. you will have to drill a hole the diameter of the anchor. pour some cement to secure and then do the rest

Answer 5

Norm is right, unless you want to go to the expense and headache of cutting out the concrete. The simplest solution is to buy a post anchor and secure it to the existing concrete. Decks using a pier system have used this type of construction for years without problem.

Answer 6

Rent a cut-off saw and concrete blade from your local tool rental store, cut 12"x12" blocks out of the concrete, dig your holes to depth (24" is code in my area, Chicago) with posthole diggers, then set the 4x4s plumb, with concrete.

Anyone that answers otherwise below me, talking about "bolt-on" anchors, has no idea what they are talking about. Your railing will be so flimsy, you may as well have no railing at all.