This Is One of the Biggest Problems Keeping Floor Joists Straight

[aaronroberts]

The way I've always done it is to lay a 2x4 over the top of the floor joists. Space the joists correctly and nail down the 2x4. Then cut half the blocks you need at exactly the correct width and install every other one. Finally you come back and measure and cut the missing ones individually and this takes care of any abnormalities in the wood. Saves a ton of remeasuring time and the plywood never misses the lips.

[huejanus]

I usually tack a 1x across the top of the joists to hold them at 16” oc and measure the spaces. The spacing usually runs from 14 1/2” to 14 3/8”, that 1/8” difference, if not taken care of, can add up to a lot of problems.

[johnr.]

Excellent warning. I've built some sheds and outbuildings and wondered how things got "off". To correct the problem (drift) after the fact, I had to add 2 x 4 extensions to the floor joist for the neighboring plywood sheet to anchor into. More often I encounter this problem when fixing someone's old job like a deck with nails or screws that have popped out because the drift or spacing was not corrected when it was being built.

[GGg-ugjr]

I've experienced this in real life doing what I do. The cause of this I found to be joists that are cupped. If you're joist is cupped and your block is cut square on one side you'll have a gap in the middle of your block and the other side of that choice you would have a gap on the top and bottom. Good information here and good solution trim a little off when you need to.

[SBNewMe]

Great video - easy to assume everything is square, or for whoever did the blocks to not really think it matters. How about laying the sheathing down at the outside edges first to see how the beams (rafters) line up - then do the mid-span blocks?

[erinkennedy]

I cut my blocks a 16th short and have been living in my house for a year now. it's been interesting seeing the lumber shrink up. I ended up with the blocks causing squeaking in places but was lucky to have access to add some 5" screws to fix that problem.

[turville]

Very timely . I’m building stud. Walls 3m tall by 10mx5m for my new gym in my barn. Im still trying to work out how to put a floor in about this structure. First time DIYer . Thank goodness for youtube

[marksokolski]

Was about to start blocking my floor and saw this, SUPER HELPFUL thanks 😊

[jonwikan]

When I work alone I hook a tape and stretch across the room. If something starts to drift I can adjust accordingly but I like the idea of having a jig prebuilt for every job. The other reality is not every joist is exactly 1 1/2"

[drew]

As a framer, I'll usually mark a board out at 14.5" increments (29", 33.5", etc) and then when cutting, take the saw down the middle of the line, so the 1/8" blade takes 1/16th off each side of the cut. Installed, these usually slide in with just a touch of tension, and work out to be within a 1/16" of layout even after 10 ft or so, and that's more than good enough for framing. In framing, you almost always find that stacking layers, you gain a little bit. hence taking a little off each block works out perfectly.

I would double check layout every 8' or so, every other joist is excessive and wastes time. Even if you're a 1/4" off layout, that's acceptable, more than that is getting sloppy though and going to increase the likelihood of squeaks from shiners

[Novasawildone]

We're about to raise our sunken living room so thank you for this. I actually love checking to see what videos you have when trying to think through a project.

[byronmilla]

This is great !!! For teaching with out wasting lumber!!! 👍👍👍

[AsItHappensHere]

if you only measure back to the last joist to assure 16” OC, you will still get amplification of error over distance. Either measure back to the START point for each on (which is too time consuming) or tack down a story pole / jury stick first.

[richvail]

Very thankful for the heads up. Starting in the spring to build my camp. Saving this video for a better build.

[chaconjohnson]

I'm glad I watched this. I always gain from your videos. I'm doing a foundation with three beans 20' long and 5' apart. I was considering adding blocking at 2.5' across but after watching your video, now it seems like a waste of time and unnecessary. Would you agree?

[bobblaszczak]

You also could lay the plywood down and make sure you’re hitting joists and put blocking in after either all of the sheathing is down (from below), or as you approach the point where blocking is needed. Glue the blocking. It helps with squeaking.

[EmileJrManigat]

Thank you for this video. I am glad I have found it before starting framing my floor.

[superwiseman]

I always put midspan blocks because it greatly strengthens the joist. Also, I used construction adhesive with the blocks- avoids and squeaks.

[jonwikan]

Greg, great video! I also see people laying out block on a long 2x10 etc using a speed square, so would this framer be essentially losing 3/32-1/8 from the blade kerf after cutting each piece? I guess it would create a bow in the opposite direction. After 8-10 blocks you are an inch short. I noticed my brother does this type of work with a partner so he can call out the measurement in real time after he nails the block in. That way he can keep checking as you go.

[ericking]

Another thing rookies don't know is EVERY top nail IS a squeak as well.Pulled up to a completed underfloor the other day.EVERY block was top nailed.LOTS of subfloor glue is also a good stopgap measure.