End Grain flooring question

[TongueTied]

I'm looking at doing an end grain floor. I'm planning to make a few test pieces (1000mm x 1000mm or so) to see how it turns out before tackling the actual floor but I was wondering if anyone here has done it before and what I should watch out for. The floor is a concrete slab so I expect to put down 19mm ply and then 20mm end grain bricks glued to the ply. I'd prefer to do 40mm end grain blocks only but don't know if that is advisable, i.e. glueing the end grain blocks directly to the concrete. Since this is basically, a parquetry floor but with end grain blocks/bricks, should the blocks be tightly packed, spaced 1mm apart e.g. like tiles, etc? What sort of expansion/contraction should I expect?

Before I get the typical don't do something that is not normal, please do a google search on end grain flooring or end grain cobbles. I'm happy to hear reasons not to but only if you have looked into this first.

[woodPixel]

Interesting to follow this one.

Doing end grain chop boards is hard work on the machines, it will be interesting to see how this goes for a big surface.

[Skew ChiDAMN!!]

I'm planning to make a few test pieces (1000mm x 1000mm or so) to see how it turns out before tackling the actual floor but I was wondering if anyone here has done it before and what I should watch out for.

Very good idea! I haven't laid thick end-grain slabs on any larger scale then countertops, but I've thought about it so I'm watching this thread with interest.

The floor is a concrete slab so I expect to put down 19mm ply and then 20mm end grain bricks glued to the ply. I'd prefer to do 40mm end grain blocks only but don't know if that is advisable, i.e. glueing the end grain blocks directly to the concrete.

I wouldn't glue 'em down... fix them down with something like a Sika/Silastic product that retains long-term flexibility with adhesion, certainly, but definitely not a rigid glue. I believe the blocks should be glued to each other though.

Since this is basically, a parquetry floor but with end grain blocks/bricks, should the blocks be tightly packed, spaced 1mm apart e.g. like tiles, etc? What sort of expansion/contraction should I expect?

I'd butt them together snugly, no gaps, preferably with the blocks as dry as possible (ie. at their lowest EMC) so as they absorb moisture from the environment they'll expand and close up any gaps. Do NOT do it the other way around (lay at high EMC) unless you really like the idea of gaps opening up everywhere.

Because Tangential movement is usually more than Radial movement I'd also spend a few hours looking at the end-grain of all the blocks and determining ring directions to save time when it comes to actually laying the floor. When working with jobs like this that involve adhesives, etc. over largish areas, you want to keep the work flow moving along as quickly as possible.

Mark arrows on the ends to indicate "the heart was this way" and when it comes to laying the blocks orient the arrows in a pseudo-checkerboard pattern so that half are oriented in the North-South direction and half are oriented to the East-West. There'll probably be a few that the heart was on a diagonal (ie. NE-SW or SE-NW) and I'd treat them pretty much the same way, mixing them in apparently randomly but with an even distribution over the whole surface.

This should 'even out' any timber movement so the floor moves equally - on average - in all directions at any given local spot.


Does that make sense to you?

[TongueTied]

Yeah, I think so. I made 4 small test pieces this afternoon (about 400mm x 300mm) each slightly different. I'll sand them and poly them tomorrow to see what they look like. I've done them at what I was expecting to be half scale as I don't have the larger wood yet.

I think in order to vary the direction to the heart wood as you have suggested, I'll need to be careful to sourcing the wood and the cut of the wood to get as much variation as I can.

[Joseseat]

Use bostik ultraset. That is what we use when laying floorboards. Ply first, using concrete pins at recommended spacing, usually every 200mm. It is a lot of pinning, drill with a masonry bit and then whack a pin in with a mash hammer (small sledgehammer).