remod problem

[hellcatt200]

This is more a remodel problem than a WW problem. I have an old house. It has actual 2x8 floor joists. The problem is the floor is sagging and getting a little bouncy. I have a full basement ( shop in basement ) so i have great access to the joists. My question is:
Should I get more 2x8 and push them up to the floor and nail in or:
Buy 2x10 and rip them to size and install them.
I will "sister" the joists to old ones in either case. I am leaning to getting the 2x10 and rip idea. Any advice would be nice. This is just one ( of many ) honey do things to the house. When I started renovation I found a building permit from 1918 on a heat duct. I told ya the house was old lol.

[oldslowchevy]

well frist thing i would do i make sure there is no rot or infestation of any kind then i would ggo with 2x10s but just notch the ends to fit the sill plate and the beam i think it would be stonger

[Pipestone Kid]

I agree with osc on checking for rot etc. I don't agree on using 2x10's. As soon as you notch them the are only as strong as the notch. Is there bridging in the joist? If not, several rows of solid bridging will do wonders. How long is the span of the 2x8's? If it is over 10 ft. I would suggest putting a strip of valley tin between the old joist and the new one before you nail them together. (Try to bend an eight inch piece of tin if it can't buckle)If you add solid bridging, one row of tin on about every third joist would be more than sufficient.
Jim

[Wood_Junkie]

We had an identical problem in our old house. Actual 2x8 oak joists. We actual had a strutctural engineer come take a look since it was our 2nd floor bathroom floor / dining room ceiling and we were doing major upgrades to the bath upstairs. (FYI, this was about 2 months ago so it's not outdated 'thinking')

Two things:
Notching the boards effectively makes the "hanging" extra irrelevant since it's not sitting on the sill plate or supporting wall. If you were to reverse it and the notch was on top, then the extra width makes a difference because it's fully supported. But he said once you cut away the side support, there's no reason to leave the extra. Based on that, I'm passing along the advice to rip the 2x10's down to match and sister them.

Second, bolting the sister boards at the end and spaced along the center provides a lot more strength and stability (according to eng. & contractor we used). Also, glue along the length and a few heavy duty nails, between the bolts, coming from both sides.

[cat44]

Hellcat,
What is the spacing of the joists? What is the span? Are they actually 8” deep as with some old houses? Or are they 7 ¼? You could sister with an LVL every other joist, or even every 3rd joist depending on the span. I think we need more info before we can post the best solution.

Drew

[hellcatt200]

There is actual 2x8x 12 ft joists now. The span is only 11.3 feet before it rests on the main beam and the sill span. There is no rot or decay but the boards are obvisiously old and getting weak. I would like to get 2x10x12 and rip down to a 2x8 and sister new one in. I will use 6 inch carraige bolts and nails. The glue idea is new but i will use that now that i know about it.I agree with the noch idea.. lots of extra board not in use that way. After new board is installed i will also put the stabilizing "x" boards in. Hope this new info helps...edit.....15-16 inch on center spacing ...I don't think they had tape measures back then lol. even the wall studs are 15-16 inch on center.

[TOD]

Why pay the 2x10 price just to cut it down to 2x8?

[oldslowchevy]

becase a 2x8 back then was 2x8 but now it is 1 1/2 x 7 1/2 where as ripping a 2x10 you can match to the same size

[cat44]

I think you should rip the 2x10s down to size and sister them up. Then put in solid blocking as someone already suggested.

[ballistic bob]

I would find a sawmill near you get some real 2x8's glue them with Pl premium and 3 inch scerws every 12 inchs hi and low block every 4 feet one vert and one horiztial scewed together level with the joists

[garager]

Build a temp. wall in basement for the height that your ceiling should be. Your going to use this to level out your sagging floor. Bring the wall up to your floor joist and gently pound the bottom of your wall so its standing in a plumb position. Listen to your floor in between your banging. If you try to bring up your floor with pole jacks or what ever, the single pinpoint area can bust your cement floor, because its not thick enough (no footings under), you need to distribute your pressure area. The concrete will not be perfectly smooth so you must use shims in the space between concrete and bottom plate on wall. Before you do all this, make sure your new floor joist's are up in the cavity or you could be taking down your wall and doing it over again. Pound your new tie in position up against old joists and screw them together with structural screws. I hope your floor up above isn't in a finished condition. Not all home centers carries structural scews so call and ask around first. Should pass any inspections I do believe, usage of glue I don't know about that waste of time and money. Good luck with your renovation, done plenty myself.