Hardwood Floor Glue Adhesives
Gluedown Adhesives General
Adhesive types used for glue down installations add considerable costs to any installation and there’s a reason for it. It works best! 
Often ill informed handymen or the weekend DIY types are persuaded in choosing the ones that are a few hundred dollars less. After all, it says flooring glue. Right? Wrong.
Folks, have it done right! Sure, that premium adhesive that sells for $190.00 for each five gallon container may be $ 100 more than than the other stuff sitting on Home Depots' shelf, but does it say it can be used for hardwood installations? Shortcuts taken from amateurs and professionals alike will often void installation warranties, not to mention complete failures and a horrible chore of ripping that new floor out.
Urethane Adhesives Gluedown
By far, urethane adhesives are used more predominately than any other hardwood adhesive today. Hardwood manufacturers that don't offer their own specify it more than any other. It is not entirely friendly with the environment, but is vastly improved from higher solvent adhesives that were banned by the 
EPA in the 90's. Bostiks or similar type products should only be used with solid gluedown floors, but that's another can of worms as well.
Although solid glue down installations are a grey area, installed by proper specifications they can be just as successful as using an engineered hardwood (more often recommended with concrete). As a side note, I don't advocate the installation of genuine solid 3/4" products with these types of adhesives. Reasons being many installers do not follow procedures well enough. Thinner solid products are safer to use because of the product flexibility.
Uptown glue down product specifications
There are many urethane adhesives on the market today with Bostiks currently the market leader. Other names include Taylor, Mapei, DriTac and Sika. When using any urethane product it becomes paramount (fancy words are not common on this site but necessary here) a cleanup schedule be followed. Double and triple check no adhesive has been left behind on any installation immediately and after the end of the day in proper light.
Another drawback with urethane adhesives includes the workability. Workability in that they are much harder to spread compared to water based or acrylic adhesives. Taylor MS Plus, which also works as a sealer, has been gaining popularity (one of our recommendations with our own hardwood line). in recent years due to it’s ease of use and cleanup.
Water Base Adhesives Gluedown
Over the years one water based adhesive has stood out above the rest; DriTac 6200. The adhesive 
spreads extremely well compared to urethane, whose makeup is generally thick in consistency. Benefits with DriTac include a sticky or tacky makeup after the adhesive bonds with the sub floor and hardwood.
Only to be used with engineered flooring, the adhesive is ideal for gluing longer wider boards, opposed to the stubbornness of many urethane products. In essence material will slide more easily and not get hung up with the aggressive suction characteristic of urethane.
Many professionals do not advocate the plop and slide method with glue downs, but there are times a board may inadvertently be dropped into the adhesive away from where the tongue and groove will engage. With urethane the board is extremely hard to move into position, opposed to using DriTac. One disadvantage of DriTac is the memory it builds once moisture evaporates after spreading the adhesive. Let's try another description.
Depending on humidity levels, the adhesive will lose (flash time) moisture after it is troweled to the subfloor. Let's say in your region flash time is 90 minutes. Approaching that 90 minute interval the adhesive is not tacky to the touch, but once a board is laid into the adhesive it grabs immediately. It almost functions like that of a magnet. If you happen to lay the board with a slight gap and try to push it into place it will spring back to its original position. It has gathered a memory.
Another benefit of DriTac over urethane lies in the tacky nature after the installation. Engineered products offering a minor banana effect will have better performance with this adhesive. If in doubt of the contact with the subfloor and adhesive, weight can be applied on questionable areas the following day. Once the weights are removed, a superior bond takes place, opposed to urethane that offers no simple corrective action.
Cleanup Methods: Water dampened rag before adhesive sets. Mineral spirits after full curing.
Multi Use Adhesives
In recent years manufacturers have developed adhesives that serve more purposes than just for gluing down hardwoods. Bostik in particular has developed a urethane adhesive that serves two additional purposes. Installer reviews are positive in that it is also easier to spread opposed to the harder Bostiks Best product. Additional benefits include:
See The Video• Moisture vapor protection
• Sound reduction properties
Floating Floor Glues
While some manufacturers offer their own proprietary glues for floating floors such as Bruce and their Ever-Seal, Kahrs and their Landobond floating floor glue, 
the professional choice has been Titebond Tongue & Groove Flooring Glue. On another note, manufacturers have different methods for applications with floating floors, which can also be found true with spread adhesives mentioned above.
Cleanup Methods: Water dampened rag before adhesive sets. Careful peeling or scraping with a plastic scraper after glue has cured on surfaces.
Special Note: Use of mineral spirits and cleaning hardwood flooring should only be performed in moderation and away from any potential heat or flame source. While most prefinished hardwoods are resistant to mineral spirits it is advisable to test any finish before application. Proper ventilation should be provided as well.
