Bostik Adhesive

slehman

What is the real differance, not just what is listed on a side by side list, but in terms of working with etc. of Bostik Best and Bostik BST? I know that Bostik Best is used a lot, but what about Bostik BST?

smadax

I know I've revived an old thread, but I did a search on this product because I had the same question...

I've talked to the supplier and they've said Bostik Best is a sealant/adhesive. Bostik BST is only a sealant.

Floordude

UHHH??? I think they are confusing BST with MVP, their moisture blocker membrane.

BEST does not hold the trowel ridges like BST does. Neither BEST or BST are moisture barriers alone. They have properties of a moisture barrier, but troweling does not leave sufficient build thickness to achieve a good perm rating.

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smadax

Always encouraging to discover I've been given the wrong information!

So, what is the difference between BST and Best??

smadax

I called Bostik Tech Service Dept. 1-800-523-6530 and he stated;

"For radiant heated concrete floor, if the moisture is in excess of the manufactures wood floor requirements, then the MVP would need to be applied as vapor barrier, with a recommended adhesive such as BEST.

However, if the moisture levels are below the manufactures requirements for the wood floor being installed, you can use Bostik BST independantly."

astor

Best is "moisture cure polyurethane" adhesive and I think BST is "urethane" adhesive,I only use Best or Ultra for easy spreading,once I used BST and did not like it.

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smadax

http://www.bostik-us.com/Files/TDSFiles/BostiksBest.pdf

http://www.bostik-us.com/Files/TDSFiles/BST.pdf

What happened when you used the BST, why did you not like it?
I'm tossing between the idea of using either method...

MVP with BEST
BST only

Not sure what to do because it's a new type strand floor and we're guinea pig installers for this application over radiant heated floors, where we can't put down subfloor because we can't add too much height.

Bodger

A while back, I had 2800 sf of flooring in a new house. Woven strand solid bamboo, over Warmboard radiant heat system.

The Warmboard folks would only warranty if the flooring was installed with a urethane adhesive. Something to do with some types of adhesive can denigrate the pex (or pex-like) tubing.

That's what we did, or I should say my flooring sub did. I'm a GC.

smadax

Talked to another supplier for Bostik and like his idea...

"Take Bostik Best, apply one layer with flat trowel just to put on a skim coat for as vapor barrier layer. Then trowel on as per instructions for flooring installation adhesive. Install the wood floor with the groove in the opposite direction to prevent plowing the glue with the groove during installation."

They recommend Bostik Best because the warrant is better than BST and with radiant heated flooring MVP would be a little much. If the heat is turned on for 1-2 weeks it should be fine to install without moisture worries.

Floordude

Both BEST & BST are moisture cure urethane.

I like BST because it holds the trowel ridges better. BEST slumps to a pancake, unless it is an old bucket and starting to set.

Before MVP, Bostik use to recommend troweling BEST on and letting it slump and set up. Then the following day, gluing the wood, using BEST.

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astor

I have started using Best when I did the GAP stores in Canada in 1990's. Installed and serviced these 40+stores for any flooring problems over 10 years.Half of these stores (each ave.4000 sq.ft) was installed with ULTRA and half with BEST.As you can imagine we needed to be quick to get the job done and two guys just spreading glue non-stop.Ultra and Best allowed us going fast.
I look for end results:specially when I have to replace the part of the flooring due damage.The floor boards with Best holds much much better than BST or 811.A junk of slab usually comes with it.(same with ULTRA-if you do not mind paying some more).I can remove floors with BST much easier.
"holds the trowel ridges better" it does not make it better.
"BEST slumps to a pancake" does not make any worse, actually it is very difficult to pull it off the floor during installation if you want to remove the board.it just sucks the board into slab
Do not forget tpo roll the floors with 150 lbs roller after couple of hours,not a must but I do it anyway.

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Floordude

I was informed on a nightmare take up that was stuck like poop on ass- wipe, it was Franklin 811. One of the hardest I have ever removed.

I use a lot of Mapei 980 and 990, along with Taylor's cross linkers for the green crowd. Bostik's doesn't impress me all that much. I can say for a fact, that Best does not suck the wood down, but I know what you mean, all urethanes have that characteristic, when trying to pull a cull board out of the glue.

I have had to do board replacements with different adhesives brands and types used, including BEST, and no glue was really any worse then the other to get the boards up, unless it wasn't bonded in the first place and the adhesive grew legs(no transfer) Which reminds me of another thing with adhesives that slump, Like BEST and Sika T-55, they are so runny, even a slab within flatness specs you will be chasing hollow areas, even when rolled with a 150# roller.

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