Kitchen and Laundry project, joists and all...

[vm428]

Hi Everyone!

I have been reading lots of old posts and am so happy to have found this incredibly helpful forum! My husband and I really appreciate any advice you are willing to share.

We are DIYing, trying to prep our 1950s kitchen & laundry for tile and ensure the floor supports the weight of our appliances and future countertops.
Fridge is 330 lb, range 350 lb, and we hope to install stone countertops later (probably granite, possibly soapstone).
We would be happy with a porcelain tile floor, but would like to have the option to do natural stone if it isn't super hard to get deflection up to par.

We are in the Greenville SC area.
Kitchen is 12 X 9.5" over crawl space.

There was a sink leak many years ago, poor repair job, and the floor dipped around the sink. The subfloor was plank, joists were 2 x 8, 12'3" span, 16" on centers, notched 3" at the support beams, and one joist was cracked near the sink. Based on what I read here, and your Deflect-O-Lator not liking our joists, we tore everything out.

We decided to replace all of the joists with double 2 x 8's (there isn't enough room for 2 x 10's). We also added a 2 x 8 (glued and screwed 3" deck screws top and bottom at ends and every 16', zig/zag pattern) to the main beams for the new subfloor edge to rest on, which reduced the span a bit.

The new joists are double 2 x 8's in hangers, 12' span, 16" on centers (a few are slightly less than 16" because of things in the way).
We have 3/4" sturd-i-floor to use as the new subfloor.
We are planning to use Ditra under the floor tile.
We are going to replace joists in laundry room as well over next few weeks and will run the tile through kitchen and laundry.
We are going to improve the crawl moisture barrier, I will probably have questions about that later.

The joists are currently sitting in the hangers but are not toenailed in yet.
1) Does what we have done so far look/sound OK?
2) Should we toenail the joists as they are, or should we glue and screw the sisters together first?
3) Would blocking or cross bracing be better in our case, and where should we put them?
4) Do we need to do anything extra, bracing/support wise, for the range or future stone countertops?
5) Options for getting the deflection rating up for natural stone (joist #4 close to center of room is sitting on a column)?

I will have more specific questions based on what you guys advise. Thank you so much!

(I will try to take photos the right direction next time, can't figure out how to rotate these)

[cx]

Welcome, Vena.

1. Best I can tell from over here, yes.

2. You don't have sisters, you have doubled joists supported at both ends and there is technically no need to glue or screw them together. I'd put in some screws just to ensure no squeaks later, but that may not be at all necessary.

3. With doubled joists, probably not. If you elect to do so, cross-bracing near the center of your span would be the most useful.

4. I would not think you need any such if you do the counter tops before you set your floor tile. It's the added weight in the middle of the floor when the tops are being delivered and set that would be the consideration. If those new joists are of good grade and species, I wouldn't even worry about that. See my warranty information below.

5. You'd need to have some mid-span support for your joists to get to the required L/720 deflection required for natural stone tile. But there is at least one manufacturer of tile installation products that will warranty an installation over joist deflection as high as L/480, which you already meet.

You will need a second layer of plywood subflooring if you elect to use stone tile, though. No way around that.

My opinion; worth price charged.

[ss3964spd]

Welcome, Vena, you two have been working hard!

Running your joist structure through our Deflecto tool with your double 2X8's, 12.5 foot span, 16" OC, the joists won't support a natural stone installation. Even if I tighten up the spacing to 14" OC, and reduce the span to 12' it comes up short. Remember, there are two components to consider when it comes to floor deflections, how much the joists deflect, and how much the plywood deflects between the joists. To address the plywood deflection you'd need two layers of plywood for a natural stone installation; the 3/4" you're already planning on and an additional 1/2" on top of that, with both layers installed so the long edge (strength axis) of the plywood is perpendicular to the joists.

What I am curious about is that single column, supporting that double 2X8 joist at what looks to be roughly the center of the joist. If that's the case the effective free span of that joist isn't 12'3", it's roughly 6'. IOW, you basically have two 6' joists left and right from the column instead of a 12' joist. Deflecto says a single 2X8, @12' and 16" OC is L302, while a 2X8 @ 6' and 16" OC is L1520 - a substantial improvement.

This means those two 6' joists are going to deflect far less than the adjacent parallel 12' joists. In the real world I don't know if it will matter, but though it necessary to at least mention it. Others will be along with their assessments.

Otherwise, if you intend to glue and screw those doubles together you'll need to do so before they get toe nailed into the hangers. But once you do have them fastened do take some time to ensure they are in a flat plane by using a straight edge across them, and on top of them along their length. The goal is to get the subfloor floor as flat as possible which will make installing your tile easier and with better results.

[HooKooDoo Ku]

Originally Posted by ss3964spd

Running your joist structure through our Deflecto tool with your double 2X8's, 12.5 foot span, 16" OC, the joists won't support a natural stone installation. Even if I tighten up the spacing to 14" OC, and reduce the span to 12' it comes up short.

If I'm entering values into the Deflecto tool correctly, I'm showing the floor can support natural stone IF 12' sister joists are added so that the joists are effectively tripled.

[vm428]

Thank you for the replies! Yes, this is HARD work, I'm so relieved you guys didn't tell us to start over (yet)

Oops, doubled joists, not sisters

It's a really tight space, so I don't think we can install a midspan support.
Joists are #2 prime kiln dried SYP.
Sorry, I think I may have made it confusing by putting the old joist configuration in the initial post.
The new joist configuration is double 2 x 8's, 12' span, 16" on centers. I think/hope it's L/603 on the Deflect-O-Later.

So it looks like our choices are:
a. 3/4" subfloor + Ditra + porcelain tile
b. 3/4"subfloor + 1/2" underlayment + Strata Mat + natural stone.
c. add a third joist to each double + 3/4"subfloor + 1/2" underlayment + Ditra + natural stone
6) Is this correct?

7) Re Dan's comment, please let me know you guys forsee any negatives to having the shorter span at the center joist?

We are working on getting everything flat this weekend. I am confused about how to best go about flattening/leveling at the joists.
The boards are pretty straight as far as we can tell with our non-expert eyes, but they definately are not perfect.
We put them crown up.

8) Is planing the best way to go about flattening them, and what is the maximum amount one should remove when planing?
9) We've never used a powered planer. Would a rented Makita 3" door planer work?
10) If we glue/screw the doubles together, can they be planed as one unit with a 3" planer?
11) Will gluing/screwing the doubles together help minimize any warping tendencies over time?

Thanks in advance, you guys are great!

[vm428]

I don't think I am allowed to attach links yet, so here is a photo of the makita planer info...

[cx]

6. Yes

7. No downside I can imagine to having that one joist supported in the center. I just wonder, as did Dan, why that support is there.

8,9. That planer (couldn't call it a door planer) would definitely work for planing the joist tops. I have one and it's a very useful tool. A fella (or a lady fella) can make a lot of sawdust in a day for 21 bucks.

You'd really want a straight-edge long enough to reach all, or nearly all, the way across the room for getting the tops in plane. Or a laser of some sort. Long straight-edge would be faster/easier/better for making the length of the joists flat, too. A ten-footer would be nice.

10. Yes.

11. In theory at least. I don't think it at all necessary in your application, but I'm always in favor of gluing all members of subfloor structures together.

My opinion; worth price charged.

[vm428]

Early to bed and early a.m. to the crawl space we go...I'll be back

Thanks again! You guys' advice is so helpful!

[HooKooDoo Ku]

Originally Posted by vm428

We are working on getting everything flat this weekend. I am confused about how to best go about flattening/leveling at the joists.
The boards are pretty straight as far as we can tell with our non-expert eyes, but they definately are not perfect.
We put them crown up.

I'm thinking your biggest issue is going to be any relative difference in height from one pair of floor joists to the next.

I had to deal with a similar issue (but from underneath) when I finished in my basement. The living room was built with 2x8 on 12" centers with a 14'6" span. The floor was very bouncy and I took multiple steps to remediate the bounciness.

By the time I finished stiffening the floor, what was now the ceiling for the room downstairs was no longer flat to the point it was going to cause issues installing drywall for the ceiling.

So I used a 4' level and a belt sander. (Given I was on 12" centers and you are on 16" centers, that would be equivalent to you using a 6' level)

Basically, anywhere I could lay the level across three or more joists and a joist in the middle was a bit proud allowing the level to teter-todder, I'd sand the proud joist in that area. I would test not just laying the level perpendicular to the joists, but also at various angles.

[vm428]

ugg, I'm glad we are not working from underneath as you had to do, that seems even more difficult.

We will be sure to check across 3 or more joists and in multiple directions.

Thank you

[ss3964spd]

IMO, Vena, you do want to glue/screw the joist pairs together, otherwise you effectively have two 12' 2X8's side-by-side. If, say, when laying down your plywood (with the long edge perpendicular to the joists) the edge of one sheet lands on one joist and the edge of the next lands on the other you won't get the benefit of the doubled joists. Gluing and screwing them together basically creates one nominal 4X8 joist (actual 3X7.5).

You might also ensure that the ends of the joists actually sit on the bottom of the hangers, not just the corners of the joists resting on the rounded left and right bend of the hangers. Be sure the joist tops are even with the top of the rim joist that the hangers are attached to. Shim or trim the ends as necessary.

[vm428]

Thank you again for your help!

Wasted half of Saturday fighting with the rental planer before returning it.
So we caved, bought one and tested it out. I like planing Will retry getting things level this weekend.

We did glue/screw the doubles together and they feel "studier".

Originally Posted by Dan

You might also ensure that the ends of the joists actually sit on the bottom of the hangers, not just the corners of the joists resting on the rounded left and right bend of the hangers. Be sure the joist tops are even with the top of the rim joist that the hangers are attached to. Shim or trim the ends as necessary.

12) Joists are still not toenailed in. Does it look like we need to do anything to these joists regarding how they are seated in the hangers? I think one is good, 2nd has slight tilt on one board, 3rd both boards touch the back but there is a slight space at front.

13) We're using an 8' level. There is one joist that looks like it will be between 1/8 and 1/4" lower than the others after we make adjustments. Would it be reasonable to glue a piece of 1/4" of lath/wood (same width and length as joist) to the top of the joist and plane it to the correct height?

[ss3964spd]

12) 1st and 2nd look fine to me. 3rd would probably be ok with the nails, but I'd probably still stick a shim in there just to be certain - because I'm just that ridiculous about little things like that. Make sure the top of the joist (all of them really) is even with the top of the rim joist, nail it in, then put a bit of glue on top of a wood or composite shim and tap it in.

13) Sure, if you think you can figure out how to glue and clamp it along its length. I'd use wood glue, not something like Liquid Nails.

[cx]

13. I think far better to put shims under the joist ends at the hangers and to get the tops as close as possible to being in plane with the other joists and then plane as little as possible to do your final adjustment. Get as much contact area as you can between joist end, shim, and hanger. I'd want a dollop of construction adhesive between shim and joist.

My opinion; worth price charged.

[vm428]

OK, we will do some shimming in the hangers.

Thank you