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how to jack a porch

Posted: Wed May 11, 2005 11:00 am
by grant2772
Hello everyone,

Well here I am faced with an intimidating project. Jacking my porch. The porch has begun to sink in the front, making the exterior of the house look tired. I cut an entry way into the side, and found a poor patch job from the PO's.

First off the ground is loose dirt, nothing for a firm footing for the posts.
I am trying to avoid pouring cement, so I put 1/4 down gravel under there. My plan is to use 4x4's in the preformed cement blocks you can buy. These blocks I plan to put on top of cement pavers.

For some reason, there is already a ledger board on the house, but nothing is attached to it? The joists for some reason run paralell to the house. What I was thinking of doing was to run joists perpindicular under the existing structure to make it stronger.

It appears that the PO's would jack it up every once in a while, and shim the supports with blocks of 2x4's. I don't want to be doing this every couple of years, so I think I'm on the right track with my plan. Am I ?

What should I do first? Jack up the porch to where I need it to be, and then put in the new joists, or should I run the joists and then jack it up?

Second, distance between the ground and the porch is about 4 feet. What is a safe way to jack this up? I should mention I have picked up 3 bottle jacks, but for obvious reasons, I am terrified of a 4x4 kicking out during the process.

Sorry if this is long, but I dont want to start out only to find out there is an easier and safer way.
Thanks in advance,

Posted: Wed May 11, 2005 11:51 am
by jeepnstein
You'll be better off pouring some proper footings. The cost will be about the same and you won't ever have to deal with it again.

Jacking the porch is not a big deal. Go slow and make sure you have your cribbing nice and solid. If the framing is as bad as you describe, why don't you just jack the porch roof and then rebuild the porch? It would be less work than trying to do patchwork framing and leveling. You could probably re-use some of the old porch material and save a bit of money.


Posted: Wed May 11, 2005 12:12 pm
by Jack Willard
There are adjustable pole type jacks that you can rent. You can also put in staked down to the ground angle brace boards to prevent sideways movement of the jacks.

I don't quite understand why you would avoid pouring concrete piers with an embedded steel piece to bolt the 4x4 posts to; if you are already into gravel, pavers and blocks. They are much more stable.

Do the perpendicular joists first, except where the posts are. Then jack it up and put in the joists above the posts. Put in the new posts under the perpendicular joists and then lower the structure back down on top of the new posts, making a secure attachment to them.

This would appear to be correct based on my imaginings of what your porch must be. You need to describe the situation better or post a picture. It's hard to say exactly without better info.

Posted: Wed May 11, 2005 4:59 pm
by Dave
I'm in the same boat, to the letter, and will need to do it this summer. I'm going to pour footings but somehow I have to try and manage it without disturbing my victorian ballusters and railing, or the building inspector will make me bring it up to code (the rail isnt high enough)

Thinking out loud... my joists are parallel to the house too, meaning the floorboards are perpendicular. I wonder/think that maybe Victorians prefered the floor boards perpendicular to the house. Many orgininal old houses have the floor boards this way. Question is why? and would it be more appropriate to keep them that way.



Posted: Wed May 11, 2005 9:51 pm
by Steve Caraker
I'm doing the same porch project this summer, but ours isn't settling. The column bases have rotted out over the years, and been replaced with plain 2x blocks. I've gotten new fiberglass bases, and while I'm there we will replace the second generation railings with a re-creation of what we believe the original ballustrade looked like. Or at least one that was commonly done in the 1920's on Colonial Revivals.

And just so I don't have to jack the porch up again, we will be replacing the plywood deck with the original 1" x 3" T&G yellow pine flooring. Dave the porch framing was done the way you see it so the T&G flooring could be put down running out from the house, thus using shorter mat'l., no running lap joints, and any rain water that gets into the gaps will run to the outside of the porch. When I re-built several of my granite piers last year, I poured concrete pads with some small rebar grids in them-they worked out well as Jack suggests. Grant when you set your jacks up put them on pieces of plywood to distribute the load under the jack over a larger area. Stake the plywood around the outside and screw some 1x blocks around the foot of the jack to keep it from sliding on the plywood. Screw the post that you are using on top of the jack to the porch while it's working. If you take some time to plan it carefully, it's really no big deal. Good Luck, Steve

Often overlooked porch feature

Posted: Thu May 12, 2005 11:59 am
by lrkrgrrl
I'm sure you all are hip to this, but I'm going to say this anyway, because I've seen this little detail overlooked way too many times: Porch floors should NOT be level, but always slope just a leetle teeney bit away from the building...so rain water goes away. Having the floor boards perpendicular to the wall also facilitates rain runoff. The little gaps between boards carry water off instead of letting it stand.

The floor boards on my ex house all ran perpendicular to the edge of the porch: ie: the north and south end had boards running N/S and the boards ending on west side of the porch ran E/W. They met in neatly mitered angles running from each outside corner, and sloped gently down and out on each side. Sloped floors inside can be a hint that a room was converted from a porch at some point.

Dave, I'm with you on the old railing thing. The building inspector is insisting on the most appalling "improvements" to porch rails on beautiful buildings all over town. The flimsy home despot rails on my second floor porches are not much improvement to safety. (although they do keep the dog from leaping off...so far...) If you must raise your rails, consider some sort of metal pipe rail just inside the original rails. I've seen this done on rehabs of capital-H historic capital-P properties. It may not be the cheapest solution if you have to hire it out, but anyone with a little pipefitting and/or welding skill should be able to create something serviceable. Paint it black or the same color as the walls behind it and it should just "disappear." And it will last a lot longer than that...that...that...oh, JUNK (to be polite) from the McLumber Yard.
(My thanks again for your indulgence.)

Posted: Thu May 12, 2005 12:56 pm
by Guest
ABOUT THE JACKS.... The trick is to keep the jack itself up against the porch. DO NOT put a 4x4 or something else above the jack. :shock: DAMHIKT

Instead, put blocks under the jack and let the jack itself push against the porch. The only thing you'll need is a block of wood, or even better, a small steel plate 1/4 inch thick and 6x6 inches to disperse the force from the jack across whatever framing member you're pushing against.

As for a foundation, you must dig a hole and pour concrete in to create a good footer, the very least that you could do is to use packed in crushed stone for a footer instead of concrete, although that is still subject to frost heave.

Your footer should go below the frost line. In SEPA it's standard to go down 36 inches to be sure you're below the frost line.

Good Luck!


Posted: Thu May 12, 2005 3:39 pm
by Dave
Sloped porches...Ours are original, and sloped. A perceptible slope too. A noticable grade, and apparently not simply due to settling. I will restore them with slope and with floor boards radiating from the house.

You gave me an idea on the ballusters and railing. Since the inspector would make me install Muddle McCheese tinker toys, I had thought about installing a "temporary" black iron Muddle McCheese railing in their stead, and coming back later on and removing the iron and re-installing the restored ballusters. This might happen in the bitter watches of the night whilst the stalwart intentions of yon inspector lie placated in dreamy sleep, attuned to more pressing slumberous visions of failed zoning ordinances and the like.

Perhaps now I will restore the ballustrade and "sister" it with the aforesaid iron folly on the inside, which will quietly disappear some hot summer night, like the Perseids, of whom may be the only witness.


Posted: Thu May 12, 2005 5:23 pm
by Steve Caraker
Your dreaded inspector may be blowing smoke up your skirt! Here in The southeast current building codes apply only to building currently being built, or portions thereof. I know of no model code used in the U.S. that requires that existing guardrails, stairails, etc. to be brought up to current standards unless they are being REPLACED ENTIRELY. If this were true every building in the U.S. would have to be brought up to current building standards every time it changed owners. The only systems that are subject to this kind of regulation are elec., plbg., and HVAC because they if not kept current will burn buildings, create disease, and kill people (poor air quality) respectively. Even most private home inspectors know better. My own porch railings do not meet todays code by a good 6", and the restored sections will be installed at the original elevation. I am reusing the top member of my original porch railings, so my project is a restoration not a replacement. I think your guy is either ignorant or a little full of himself. The only reason guys like this get away with it is you don't have easy access to code books. I do for I are a inspector. Sorry for the rant, guys like the one your dealing with give all of us a bad rep. HTH, Steve

Posted: Thu May 12, 2005 6:23 pm
by Dave
Hi Steve,

I see what you are saying, and agree. The problem is, to make life easiest, I have to remove the entire ballustrade and integrated columns in order to replace the floor boards under it. And the ballustrade itself (rail and ballusters) is really far gone. I suppose I could turn it into a Bondostrade and try to replace floor boards out from under it, but I'd rather replicate it entirely. The inspector claims once it comes off, a new compliant one must go up.

Rants aside, I know most inspectors are simply doing their jobs, and there are both good ones and bad ones.