Thread: Acceptable variance in joist height for levelling the floor?

Your place and you are the tradie, yellow tongue will bend 3-4 mm and you will have dips, that is lows and highs.

I live in the “do it once do it right camp”. I only leave tolerances for landscaping.

i would be using packers, I would also look at placing the packers under your timber, ie loosen off your fixing, pack it to the correct height and tighten.

cheers

That is too far out of spec for my liking if that is between batterns beside each other but if you are talking about across the whole floor is is not so critical
It really is up to you as to what you are happy to live with

Fair enough I’m going to fix it ��

Update: mostly fixed. I've got everything to within about 1mm according to the laser. Next step is to run a straight edge and check for anything more than 1mm and do small adjustments.

I’m surprised to see there is no equivalent of noggins or blocking between the Timbers. Wouldn’t they play a useful role in stopping twisting etc?

Originally Posted by Arron

I’m surprised to see there is no equivalent of noggins or blocking between the Timbers. Wouldn’t they play a useful role in stopping twisting etc?

They are a battern fixed to the slab so no need, in conventional bearers and joists you dont block either. Blocking is best avoided if it is not necessary as it is the most common cause of squeaking. All the manufactured joists are designed not to have blocking fir thus reason and as well as the labour saving aspect

Originally Posted by lemerv

Me again!

I've finished putting down the pine joists. Lot of work! But turned out well.

IMG_5260_smaller.jpg

For various reasons I didn't get them all at the same height. I've been running a long straight edge to spot check and I reckon there might be at most 4-5mm variation at some places (haven't checked everywhere yet). I'll be putting 19mm yellow tongue on it. How much is considered acceptable?

If need be I can do the annoying work of gluing some window packers on the top of the joists in areas just to make it co-planar.

lemerv,

Was there a reason to lay down the joists "flat" rather than beam-like?
Just curious!

Cheers,
Yvan

Originally Posted by yvan

lemerv,

Was there a reason to lay down the joists "flat" rather than beam-like?
Just curious!

Cheers,
Yvan

This was simply based on my reading of lots of other posts on here. From memory it helps prevent twisting of the joists and since I’m not putting in floor insulation I didn’t need the height.

But I will defer to the experts on this forum for an actual answer!

The timber has no span as the concrete below carries the load. They are not joists in the true sense of the word, they are battens.

Originally Posted by lemerv

Me again!

I've finished putting down the pine joists. Lot of work! But turned out well.

IMG_5260_smaller.jpg

For various reasons I didn't get them all at the same height. I've been running a long straight edge to spot check and I reckon there might be at most 4-5mm variation at some places (haven't checked everywhere yet). I'll be putting 19mm yellow tongue on it. How much is considered acceptable?

If need be I can do the annoying work of gluing some window packers on the top of the joists in areas just to make it co-planar.

You seem to have setup the string lines correctly with those 10mm black packers at each end and it looks like you have gone for 300mm centres, so providing each end batten is level using the laser, then all those battens in between just need a 10mm packer under the string line and on top of the batten and then just pack the batten up from underneath the timber until the 10mm black packer touches the string line, however it is most important that you have the string lines nice and tight so there is no sag in the line

Hey Lemerv, I’m planning to do something similar myself in a year or two - raising the floor of our garage about 75-100mm and then framing in the walls. Now that you have had the experience, how do you rate this method compared to just topping up the concrete slab with more concrete?

Originally Posted by Camelot

You seem to have setup the string lines correctly with those 10mm black packers at each end and it looks like you have gone for 300mm centres, so providing each end batten is level using the laser, then all those battens in between just need a 10mm packer under the string line and on top of the batten and then just pack the batten up from underneath the timber until the 10mm black packer touches the string line, however it is most important that you have the string lines nice and tight so there is no sag in the line

Yep string lines were good. But I think I ultimately struggled to work with them effectively. A few things tripped me up:
- When I banged in the hit anchors, they pulled the joists tight against the packers. But that is hard to simulate with the string line as I would need to put all my weight on the joist while also managing the string line. I stuffed up a lot because of that
- I got sloppy and didn’t always check the string line was unobstructed (idiot, I know)

If I did it again I think I would set joists down very carefully about 3000mm apart, then clamp a straight edge on them and use that as the reference to do the joists in between. I know some people said use the laser all the way but I think this could also prove tough with having to put weight on the joist while trying to get a good view angle on the story stick.

I’m sure it’s one of those things that takes practice, but for me the first time is the only time I’m doing it so happens I guess!

Originally Posted by Arron

Hey Lemerv, I’m planning to do something similar myself in a year or two - raising the floor of our garage about 75-100mm and then framing in the walls. Now that you have had the experience, how do you rate this method compared to just topping up the concrete slab with more concrete?

Hey I don’t have experience topping up the concrete so can’t compare. The joists were hard work and tricky to get right. But I got there in the end. I haven’t even laid the yellow tongue yet but I think that will he relatively easy.

From what I researched for concrete top up it would have worked out way more expensive and I wouldn’t have risked doing it myself.

I have almost zero experience with this stuff so I think when the time comes you want to start planning for yours post on here and you’ll get some great advice.

I’m also going to try and find the time to do a write up on here with lots of pics so keep an eye out for that.