1 TO 2 INCH SAG IN FLOOR, Remedy Or Cost??

JJK

A friend of mine is thinking of buying a house, it needs alot of work mostly cosmetic, However i walked threw it with him today and i noticed the floors were saging about 1 to 2 inches towards the center of the house. I've remedied this problem before but in a house with a basement. this house has an 18 inch tall crawl, with no access. We were planning on replacing the floors anyways so we will be able to get to the joist. My question is how do i jack the house back to level (not worried about drywall cracking most will need to be replaced anyways)? Is it a simple fix? OR How much would someone who nows what the are doing charge (ball park)?

dougchips

JJK, check out JLC they have a web-site and a monthly rag that is publish by Hanley. They had 2 really good articles in the past year about jacking up houses. Lots of pictures!

FMKConstruction

You need to use (preferably 20 ton) hydraulic bottle jacks to raise the house. The average height of these jacks is 12" although they are adjustable with a screw cap. I have alot of experience jacking houses and making structural repairs. Pricewise, for jacking to level within the maximum tolerance of the house, I would charge between $1,000 and $3,000 depending on various factors of the house. Then between $100 and $400 per pier depending on dimensions and whether frost or floating. Finally, if an existing girder needs to be replaced or if it requires a new install the charge is $50 per linear foot of new board. If you plan to do this yourself here are a few pointers. First check the attic and make sure the rafters have collar ties or trusses exist. Create access to crawl space and plenty of lighting. If rotted or non existant girder Use 6"x6" or 4"x4" (the longer the better) beams laterally across the floor joists with jacks set approximately 8' apart (6' if using 4"x4"). Place a 2"x12" at least 12" long under jack if ground is dirt to create a footprint (you'll go down before going up) - if concrete pad, disregard this step. use 2' or better blocks of 6"x6", 4"x4", 2"x, 3/4", 5/4", etc... to crib the house up if/when the jacks max out then add material under and/or over jacks to gain height.

good luck,

I hope this information proves helpful.

AllGoNoShow

I'm in the process of doing this as well but i have a basement-can't imagine doing it in a crawl space!

FMK- I'm curious, why 20-ton jacks? I am only using about 8-9 ton jacks and it is doing fine (of course I have 4 of them-2 on each side of the columns i am replacing in a 1100 sq ft. 2-story house). The permenant 4-inch range adjustable "lally" columns that are used in new construction are only max-rated at 7-8 tons and that is for permenant support and adjustment.

JJK

Thanx Fmk
Your info was very helpfull.

Chris G

That seams like a lot of sag to take out of the joists. Can you really take that much 'memory' out of a piece of wood? I've raised a floor at the sides, but never the middle. I'm no expert on the subject, just asking.

FMKConstruction

20 Ton jacks may seem like overkill, but better safe than sorry. I often jack houses that are occupied and full of furniture, etc... Also, it is very unnerving when you are laying on your belly in a crawlspace and you hear nails popping and wood creaking and so on. I find comfort knowing that my jack is capable of handling the weight, just one less thing to worry about.

Here's another jacking tip: before storage, always push the jack completely down (unextended position) and make sure the release valve is tightened. This prevents hydraulic fluid loss and assures that the jack is ready for the next use.

FMKConstruction

Placement of a girder will support the center of the house and retrain the joists over time. Another way to assure a proper fix would be to sister the joists with equal dimension lumber.

wickedcarpenter

I agree with sistering the joists with new ones.

BULLHART

At least you're tearing up the floor. Id hate to try and get into that crawl space and do anything...lol. I agree with those above. Id sister it heavy, I dont mind a bit of overkill in a situation like this.

Joshua

How long are the joists and is there anyway of retrofitting a "beam on pier block" fix to support the joists after you have them lifted into place? Sistering joists to the existing joist may work for awhile but could result in the same sag overtime though maybe not as drastic as 2".

skymaster

Since you were planning to repair/replace floors anyway, why not just rip it out make shure sill plates are sound and just go back new with TJI's or floor trusses? Sistering is a good ideas but seems more work than just replacing em. You have to jack each one close to level b4 sistering to do it really right. Just my humble opinion.
Jack

skylands

Joshua

In this situation, (crawl space) the more piers the better. However. In crawl spaces I find it much easier to stabelize the bearing walls and then take out the old floor system.

streetracer

If the sag is in the center of the house, it's possible a beam runs perpendicular to the joists and has some powder post beetle or termite damage. I would gain access to the crawl space and determine the cause of the sag before buying.

Larry_PCA

I would tend to agree with street racers comment to get below and see why the floor is sagging before buying if at all possible.

Depending on the age of the house (I've done two houses from the late 1700's that uses felled trees for floor joists)you may just have sagging lumber because it was undersized or as someone above mentioned a bigger problem with wood boring insects.

be prepared to spend lots of time on your back or belly, you may need to excavate the crawl space out a little to get the jack into place to us it. if you can put in girders for support great, you may as in my instance with the trees, have to put several piers and columns under existing larger timbers after jacking them up and bracing them temporarily.

Take your time, bid accordingly and most of all be safe.

__________________
Regards,
Larry Schlack
www.constructionassistant.net

streetracer

One more thing I forgot to mention. If there's no easy access to the crawlspace, there may be little ventilation. If there is little ventilation and no vapor barrier, you can bet there is soft moist wood and insect damage.

Dennis Roach

It sounds like they're doing enough work that they should just rip it up, clean it out, and make it right. Peace of mind was worth it to me.

I had basically the same situation, bought a house (+200yrs with later additions) with springy floor over crawl space with no access. I'd planned on straightening the floor as we started a kitchen remodel. But once I got under there and saw the tree trunk beams (with bark!) half eaten and soft as cheese, dirt floor, no vapor barrier, an a big dead rat. I just riped the whole floor out.

Frankly, this made the whole remodel much easier and allowed us to start with a clean slate on the kitchen and know everything was right under there. Made the plumbing and electric easier for the island, allowed us to insulate up the wazoo. The demo was nasty, but putting in the new floor was easier than making adjustments to EVERYTHING else in the kitchen.

Then my Mom bought an old house and I (okay mainly my brother) had to do it all again for her!

Rip it OUT!

__________________
Dennis
Ruby Engineering
Marine Construction - Commercial Diving - Corrosion Control

ProSide

This maybe a stupid question since I have never tried this before...But wouldnt you want to raise the floor back to level slowly....Say a slight increase in height each day? Just curious as I have also seen this before.........

EngineeringGuru

I may sound like a fool. I do believe you should investigate why the sagging has occured to begin with. There are numerous reasons for the sagging and just a simple "fix" to the problem may increase the problems in the future. Investigate before repair. Measure before you cut.

Best of luck.

747

I say tear it all out. And reframe that floor. In certain applications that can be cheaper then trying to fix what is allready there and FASTER.