Decks, Patios, Porches and Docks - Deck post heaved!
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bobntan
04-18-05, 07:59 PM
:wall: I have 3- 4x4 posts on my deck that has heaved up approx. 2" to 2.5". The other 12 posts are fine. The deck is around my 24' pool. The heaved post are on the outer perimeter of the deck. This deck is 6 years old. The posts were set 48" below grade, set in pearock, then concrete. What would be the best way to repair these posts!
Please!!!!
Please!!!!
lefty
04-19-05, 04:09 AM
bobntan,
Obviously frost heave, but I have questions about what you mean when you say "The posts were set 48" below grade, set in pearock, then concrete".
The holes were 48" deep. But how MUCH "pearock" was put in the holes before the concrete was installed? What is the frost line where you are at?
Done properly, the holes would be at least 4" deeper than your frost line, though 6" would be better, especially if you want gravel at the bottom for drainage. Then about 2" of gravel, then fill the hole with concrete, and form a cap at least 3" above grade, then set a Simpson CB44 or PB44 in the wet concrete. The post attached to that base after the concrete had cured for a couple of days.
Obviously frost heave, but I have questions about what you mean when you say "The posts were set 48" below grade, set in pearock, then concrete".
The holes were 48" deep. But how MUCH "pearock" was put in the holes before the concrete was installed? What is the frost line where you are at?
Done properly, the holes would be at least 4" deeper than your frost line, though 6" would be better, especially if you want gravel at the bottom for drainage. Then about 2" of gravel, then fill the hole with concrete, and form a cap at least 3" above grade, then set a Simpson CB44 or PB44 in the wet concrete. The post attached to that base after the concrete had cured for a couple of days.
bobntan
04-19-05, 04:47 AM
Lefty,
The frostline is 42" in michigan. There is about 4" of pearock in each hole, I then set the post and poured concrete around the post. Is it better to dig up post, or cut off post and set it on a cement slab
The frostline is 42" in michigan. There is about 4" of pearock in each hole, I then set the post and poured concrete around the post. Is it better to dig up post, or cut off post and set it on a cement slab
jayp6773
04-19-05, 06:20 AM
heaved,
lefty told me yesterday when I asked about deck posts that you shouldn't put the deck posts directly in cement. He said that they would rot if you did it that way. What you have to do is one of two things...
1. pour a 8 x 8 cube of concrete and then place a concrete post holder in the wet cement.
2. the other option is to use pier blocks.
Hope it turns out ok for ya,
Jason
lefty told me yesterday when I asked about deck posts that you shouldn't put the deck posts directly in cement. He said that they would rot if you did it that way. What you have to do is one of two things...
1. pour a 8 x 8 cube of concrete and then place a concrete post holder in the wet cement.
2. the other option is to use pier blocks.
Hope it turns out ok for ya,
Jason
lefty
04-20-05, 12:24 PM
What jayp6773 told you is kind of 'yes and no'.
The 8" X 8" cubes should have been added to the top of your footing, but poured at the same time as the footings -- a monolithic pour. Adding them now is closing the gate after the cows are gone. Pier blocks would have been set in the wet concrete of the footing when it was poured. Either way, the object is to keep the wood post above grade and out of the concrete so it won't rot.
You haven't said so, but I'm guessing that you dig the 48" deep holes (what, about 16" to 24" square??), added the peagravel, then filled the hole with concrete. The problem with that is that frost can simply apply force the the SIDES of the footing and they will heave. What you need to do -- what you should have done -- after adding the peagravel, pour in 12" of concrete, the use a 10" or 12" sonototube (round cardboard concrete form) at full length (4'). Place that in the center of the hole, on top of the 1st foot of concrete. Add about 6" of dirt around the outside of the tube, 6" of concrete inside, more dirt outside, more concrete inside etc. until first the hole is full of dirt, and then the tube is full -- giving you the concrete above grade. Then you set the PB or CB in the concrete. NOW that footing CANNOT heave. The dirt above your 16" or 24" cube in the bottom of the hole will prevent it.
The FIX is to cut the posts off at the top of the footings that have heaved and dig new footings 1/2 way between them. I don't have to tell you it's a lot of work, and it will be harder this time around with the deck above you.
The 8" X 8" cubes should have been added to the top of your footing, but poured at the same time as the footings -- a monolithic pour. Adding them now is closing the gate after the cows are gone. Pier blocks would have been set in the wet concrete of the footing when it was poured. Either way, the object is to keep the wood post above grade and out of the concrete so it won't rot.
You haven't said so, but I'm guessing that you dig the 48" deep holes (what, about 16" to 24" square??), added the peagravel, then filled the hole with concrete. The problem with that is that frost can simply apply force the the SIDES of the footing and they will heave. What you need to do -- what you should have done -- after adding the peagravel, pour in 12" of concrete, the use a 10" or 12" sonototube (round cardboard concrete form) at full length (4'). Place that in the center of the hole, on top of the 1st foot of concrete. Add about 6" of dirt around the outside of the tube, 6" of concrete inside, more dirt outside, more concrete inside etc. until first the hole is full of dirt, and then the tube is full -- giving you the concrete above grade. Then you set the PB or CB in the concrete. NOW that footing CANNOT heave. The dirt above your 16" or 24" cube in the bottom of the hole will prevent it.
The FIX is to cut the posts off at the top of the footings that have heaved and dig new footings 1/2 way between them. I don't have to tell you it's a lot of work, and it will be harder this time around with the deck above you.
bobntan
05-04-05, 08:38 PM
:) Lefty, thank you very much for the info. I was able to remove the heaved posts, plus the concrete. You were right. it was alot harded digging with a deck above you!! There is a large amount of ground water in the holes. I pumped the water out, but it returns quickly. I'm sure it is not from sprinkler lines or any other source. How will I get a sound footing, with 6" of water in the holes. The holes are 24" round and 4 foot deep. I want to do it right this time!!
Thanks again, Bobntan :thumbup:
Thanks again, Bobntan :thumbup:
lefty
05-05-05, 06:08 AM
Bobntan,
let's do it right this time. The LAST thing you want to do is to have to go through all of this again!!
Water in the hole. That has to be dealt with first. I'm guessing it's ground water rather than a leak in a sprinkler line. You are down 48", and your footing has to be 42" deep. Dig down another 3" or 4" and add 6" or so of pea gravel to the hole. That should pretty much take care of the water. Then put in about 16" to 18" of concrete. Cut a 12" sonotube so that it will stick out of the ground 4" or 5", set it in the middle of the hole, and start filling -- dirt around the outside, and concrete inside the tube. Once the tube is full, set a post base in the wet concrete. Let the concrete cure for several days or even a week before you add the post and the weight of the deck to the footing.
let's do it right this time. The LAST thing you want to do is to have to go through all of this again!!
Water in the hole. That has to be dealt with first. I'm guessing it's ground water rather than a leak in a sprinkler line. You are down 48", and your footing has to be 42" deep. Dig down another 3" or 4" and add 6" or so of pea gravel to the hole. That should pretty much take care of the water. Then put in about 16" to 18" of concrete. Cut a 12" sonotube so that it will stick out of the ground 4" or 5", set it in the middle of the hole, and start filling -- dirt around the outside, and concrete inside the tube. Once the tube is full, set a post base in the wet concrete. Let the concrete cure for several days or even a week before you add the post and the weight of the deck to the footing.