Laying subfloor?
Question:My house is 100 years old and the existing wood floors are not level. I want to lay subfloor panels, but I dont know how to level it. How do you level the floor in areas where it is not level?
Answers:
You need to use a 4 or 6 foot level.
Lay one end of the level on th high side & bring it up til the bubble is centered, & scribe a line accross the bottom edge of the level. Tack a nail in the center of the line, & use string & a line level to finish the run to the opposite wall.
Repeat this around the room.
You may not be able to get it dead on, but you can get it close.
Once that's done, cut 2x4's into wedges to fit in low to high markings. Sort of like making big long doorstops. Screw & Glue your subfloor to that.
The only other alternative is to get underneath the structure & jack it back up to level.
Hope this helped, good luck!
Snap a level chaulk line and build it up from there. go to two corners of the room to see if how far out of level it is. or buy a laser level.
Sheets of sub floor with shims to support in low areas. nail at least every foot.
If you can gut the floor to the floor joists, then you can check to see if the floor system is out of level first. If it is level, then you are good to go. Otherwise, use a laser level or sight level (if you have a helper) and find the shortest distance between level sight and the existing floor. You can then rip long shims to shim the floor accordingly at key points where the subpanels meet and then lay your subpanels. This can also be done without gutting the floor to save time.
On an older house the right way is to level it from below. For what ever reason it has settled in that area, placing extra weight on the floor (plywood is heavy) may cause more settlement in the future then again it may not but is it worth the risk? the cost to rent the jacks and the time to do it far out way the cost of the overlayment. If you thinking of putting tile over the floor you could use a self leveling compound but again this is not addressing the chance for future settlement.
I believe the easiest and the best looking way in the end to level the floor is to tear out the sub floor by taking a reciprocating saw and cutting the wooden floor on the edges. Then push a crow bar between the the floor joists and the sub floor and push up. Then proceed to cut the sub floor and nail it back down. If you do not want to do that though, you may want to spread concrete on the floor which should even out. Then grind away and sand the cement which should even the cement out even more. Then attach the actual floor to that. If you try to put a new wooden sub floor on shims it won't look very good in the end.
unofornaio is correct. You need to figure the cause of the problem first. And if possible, fix the structure first. When I was an employee, I was told to lay tile in houses where knew I shouldn't. Now self employed, I have told homeowners that they have to fix the structure first. I have lost jobs because of that honesty, but I think it is unethical to proceed with telling them of the potential problem. You say it is a 100 years old. It may have just settled and it may not deflect anymore than what is acceptable. Or you may have a structural problem that you need to address first.
If you find that it is just settled, how much? There is a difference between flat and level. If it is just a small faction of an inch out of level per 10' run, and is structural stable, no more settling, then don't worry about. The effort outweighs the results. But if has settled where there are sizable valleys and humps, but is structual stable, then some self leveling underlayment may be the solution. If it is 1" over 10' run then you have some serious issues to address. I've been in houses like that, and told the owner I can't do the work. The point is you need to evaluate the problems first.
http://www.tecspecialty.com/product_list...
This is a product for small leveling areas, if the floor is tile. I wouldn't suggest using it for large areas.
One thing to remember is if there is structual work to do then you will also have plaster work to do later.
you can pour a thin layer sand down then pull a chalk line make sure the sand is level then put down 1/4inch plywood.
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