We don’t like to do things halfway at the Greener Living Blog. That’s why we’ve given you three separate guides for each of the three installation methods: nail down, floating, and glue down. Aren’t we good to you? Now, we’ve told you there are three types of installation methods for bamboo flooring, so how do you know which one to choose? At the bottom of this piece, we’ve put a little guide to help you decide. But for those of you who already know you need the glue-down method, we’re going to jump right in… Not in the glue, of course, we’d get stuck.
Gluing down a bamboo floor
Before you start laying the bamboo planks, you have to do a little prep work. Some of it is fairly obvious, like ordering the bamboo and the glue, but some tasks are less routine, like checking the subfloor for moisture. Never fear, we’re going to go through it one task at a time.
1. Read the installation guide from the manufacturer to avoid headaches or surprises
It may look like the kind of thing you want to slip into a folder with the other user guides for your home appliances, or something you want to chuck straight in the recycling. But you’ll need this guide. This installation guide will outline many important tips and tricks that are required to not void your warranty. If you do any of the things the instructions may advise against (i.e. installing in a below-grade environment) and your floor develops problems, the company will be under no obligation to refund you. Abide by the warranty!
2. Order the right materials
Order the flooring
First, you should measure the room to see how big it is in square feet. Add 7-10% on top of that number to account for the sawing you’ll need to do plus any waste. This will prevent you from having to order another box later on, which costs you time and money. Worried about having planks leftover? Don’t be. Those planks can be stored and used to replace individual planks that could get damaged in the future, or they could be used as a test surface for cleaning products, finishes, and even sanding equipment.
Order the glue & compatible trowel
Different sub-floors require different types of glue. Always make sure the glue you purchase is 100% urethane and approved for hardwood/bamboo flooring. And always be sure to order the compatible trowel for your glue so you don’t void the glue warranty. It also helps to use Bostik Adhesive Remover Wipes to clean up as you go. There are typically 3 types of glues that are used for gluing down hardwood and bamboo flooring.
- Glues that don’t contain a vapor barrier: This type of glue is used for installing over a dry subfloor such as plywood, existing hardwood, scuffed tile, and more. These are the most inexpensive glues on the market.
- Glues that contain a vapor barrier: This type of glue is used when there’s a sub-floor moisture concern, such as a garage or crawl space. Frequently referred to as all-in-one glue/adhesive, this is the highest quality glue you can find, and it’s more expensive than regular glue because it eliminates the need for a separate second step of sealing the concrete with a primer or epoxy coating. These adhesives usually require the use of a specific trowel to achieve the proper spread rate.
- Glues that contain a sound retarder: This type of glue is used when you want to reduce the transmission of sound between levels and absorb footfall noise. Most all-in-one glues that have vapor barriers also come with sound retarder properties. There are on the market with both vapor barrier and sound retarders in them.
3. Set the right temperature and humidity
The room where you will be installing the bamboo floors must be kept to a consistent temperature and humidity level for seven days before installation. Most manufacturers recommend you set your climate control system to a temperature of 60-80 degrees Fahrenheit and humidity levels of 40-60%, depending on the average year-round levels in your area. Please check your manufacturer’s instructions beforehand.
4. Prep the sub-floor
It’s important to prep a subfloor before installing your new bamboo flooring, otherwise, your floor could be improperly installed. First things first, you have to clear and clean the room before you can begin checking for potential problems.
What does your subfloor need to support a bamboo floor?
- Level: If your subfloor is filled with bumps and dips, then your bamboo floor will be uneven, which is probably not the look you’re going for. There should be no more than a 3/16” difference in the level of the floor per 10-foot area. You may need to use leveling compound in dips, and you may need to grind down humps.
- Structurally sound: If the subfloor isn’t structurally sound and you install a bamboo floor on top of it, then it’s basically a ticking time bomb, but without the pretty wires. In a wood subfloor, you’re looking for planks that aren’t loose or squeaky with a thickness of at least ¾”. In concrete, you want to make sure that any cracks don’t go past the parge coat.
- Dry: If your subfloor is too moist, your bamboo floor is at risk of cupping as time goes on. You’re testing for a moisture level of less than 12% for wood subfloors and less than 3 lbs per square foot for concrete subfloors.
How do I fix these problems?
If the floor isn’t level, you need to sand or grind down areas that are particularly high and correct dips with wood or concrete filler, but this is pretty simple to do yourself. If it isn’t structurally sound, then you need to screw down floorboards and potentially even replace the subfloor. It’s best to get a trusted local contractor to weigh in on the best solution for your particular situation as we can’t see it through the computer. No, not even if you get your webcam out. If your sub-floor isn’t dry, you’ll need to use an all-in-one adhesive with a moisture barrier and an upper moisture limit that is high enough to seal the amount of moisture being emitted by your subfloor. If installing over a humid basement, you can use a dehumidifier to reduce moisture levels and install a moisture barrier between the subfloor and the bamboo planks. It’s also important to look for underlying causes, like a leaking pipe, that could cause issues further down the line.
5. Have a crawlspace? Make sure it’s sealed & dry
If your house has a crawlspace, then you should make sure to check it for moisture issues, as these can seep through your subfloor and damage your bamboo planks. The test is incredibly simple, and it’s fairly easy to fix moisture problems in your crawlspace. All you have to do is use a dehumidifier to remove the moisture, install some 6-20 mm polyethylene film on the floor, seal it with moisture-resistant tape, and install vents in your crawlspace. Just make sure to take a friend with you; raccoons are a common resident of most crawlspaces, and they don’t like being disturbed! Just look at the baby one in this video:
6. Acclimate the bamboo
We’re nearly at the finish line! All you have to do now is leave your bamboo planks to acclimate in the cleared room for 72 hours (or longer if your moisture levels are high). Never acclimate bamboo directly on top of concrete or other subfloors that are emitting moisture. If the subfloor emits moisture, first lay down a vapor barrier (plastic tarp or similar) underneath the bamboo flooring boxes/pallets, and ensure the apron of the tarp extends out away from the flooring boxes at least 18 inches.
7. Gather your tools
While the planks are acclimating to the room, you should gather the equipment you’ll need to complete the job. You’ll already have some of these in your home, and some are relatively cheap at your local hardware store. However, some items may be expensive, so you may find it better to borrow them either from a store, someone you know, or your local tool lending library.
- Tape Measure
- Carpenter’s square
- Rubber Mallet
- Tapping Block – made of wood or rubber
- 100% urethane adhesive with a moisture barrier – barrier level determined by your moisture tests
- Trowel – must be compatible with your adhesive to ensure the proper spread rate
- Moisture barrier with sufficient moisture cap limit – limit determined by your moisture tests
- Expansion spacer
- Tape that will not damage the finish on the bamboo planks – we recommend 3M/Scotchguard #2080 tape.
- 40 tooth (min) saw blade – higher tooth counts provide smoother cuts
- Saws; Oscillating, Table, and Mitre
- 23 gauge micro pin nailer – to work around islands and finish rows.
VERY IMPORTANT RULES TO FOLLOW: 1) Do not let the glue dry on top of the flooring finish. Once dried, most adhesives will be impossible to remove without damaging the finish topcoats, resulting in cloudy marks on your floor. Make sure to always have Bostik Adhesive Remover Wipes on hand to clean up the glue while it’s still wet. 2) Never use abrasive chemicals (i.e. paint thinner or mineral oils) to wipe up wet glue or you’ll risk ruining the finish. You should only use recommended cleaners, or adhesive remover wipes (Bostik Adhesive Remover Towels) on polyurethane floors.
Starting your installation
Now that you’ve gotten all of the prep work out of the way, you can begin gluing down your beautiful new bamboo flooring!. Important: When beginning the installation process, make sure to work out of several boxes at once. The color and shade of the bamboo planks can vary between boxes, so you can customize your floor to your ideal design.
1. Put on your safety equipment
This means hard-wearing gloves, ear protectors, and safety goggles to protect you while working.
2. Cut the planks to size
Depending on your personal choice, you may be cutting long planks, short planks, or even a mixture of the two. Go wild! Just make sure the planks are at least 8” long because the butt ends of the planks in the next rows need to be at least that far apart. Remember, measure twice and cut once.
3. Check the cure time of the adhesive
Most flooring adhesives will have a “cure time” (time for the adhesive to set solid). This doesn’t just apply to the glue that you lay on the floor, but also what’s left in the glue container. Therefore, once you’ve opened a container, you should try to use the entire thing before the cure time.
4. Pick a starting place
Your instinct may be to start in the top corner of the room, but it’s not the only option. You can start parallel to the longest wall or in the middle of the room. It all depends on the shape of the room, how it connects to other rooms, and how you want the room to look. If the room is not square and you need to make corrections, you can do so with a T-molding at doorways.
5. Start spreading the glue
When spreading the glue, start from the wall and cover the area that you think you can install flooring on top of in a 30-minute period (or however long is noted on the container). Hold the trowel at a 45-degree angle while installing, and gently apply pressure. The adhesive should fully cover the floor, so you can’t see the subfloor in the grooves left by the trowel.
Installing the floor over concrete? Make sure to achieve 100% coverage on the slab, or you’ll get a cupped floor.
6. Lay your first row
Wherever you’ve chosen to lay your first row, make sure you’ve left a ¼ – ½ inch gap from the wall to allow for any expansion in the floor due to humidity. You can mark these with expansion spacers to help you out. The gap will be hidden by moldings in a little while, so there’s no need to worry about it being visible. To establish your working line, you’ll need to find the midpoint between the two walls (taking expansion space into account) and mark a chalk line. Tap the planks together gently to get a snug fit between boards.
7. Lay subsequent rows
Once you’re sure that your starter row is correctly in place, begin installing your subsequent rows until you’ve reached the end of the section you applied the adhesive to. You should put the recommended tape across the seams of adjoining rows to prevent them from spreading apart during the drying process. Continue to spread the adhesive, and lay the bamboo boards in small sections until the installation is complete. Importantly, don’t work yourself into a corner or you could be stuck there for a while. When you reach the final row, you might have to cut the planks lengthwise to fit into the remaining space. Remember to take into account the expansion space when measuring this.
8. Walk on the floor
To ensure that the bamboo planks are properly bonded to the subfloor, you will need to walk over each plank before the curing time of the glue is up. It’s not really necessary to tap dance.
9. Pick a good stopping point
Remember, if you’re going to stop and continue the next day, you’ll want to plan. Be careful when installing the final row for the day, as you will not want to leave too much excess glue on the sub-floor. This excess glue will be rock-hard the next day and may prevent you from sliding in the next flooring plank.
10. Install the moldings
Now that the floor is glued down, it’s time to remove the expansion spacers and install the moldings to hide the gap. They can be glued down and left overnight to set, but most people advise putting something heavy on them to ensure a proper bond.
11. Clean the room
During the installation, you may have created dirt and dust that you don’t want to leave on your floors, so it’s best to sweep the floor right away. Also, it’s a good idea to check for any spots of wet glue that weren’t cleaned up during installation. It’s always best to get it before it cures.
Now, you’ll have to leave the room empty for 12-24 hours, depending on your manufacturer’s instructions. So it’s time to kick back, grab a coffee (or a beer), catch up on some good TV, or go meet up with some friends for dinner; you deserve it.
Other things to consider
There are three types of floor placement: above grade, on grade, and below grade. On grade refers to rooms on the ground level, above grade are rooms on higher floors, and below-grade floors are found below ground level (i.e. basements). The below-grade can be installed on all grades and grades can be installed on or above grade.
The subfloor is really important when using the glue-down installation method, so it’s important to check that the existing subfloor allows for the glue-down method. The subfloors that allow you to glue down the bamboo floors, include:
- Plywood 5/8″ min
- OSB 3/4″ min
- Ceramic/ marble – if you scuff the subfloor first
- Advantech OSB
- Gypcrete – if you apply liquid hardener before installation
- Hardy/cement board/backer/cbu
- Existing wood floors – if you lightly sand them before installation and check that the adhesive will bond to the wood
The subfloors that don’t allow this method are particleboard, asphalt tile, firm linoleum, firm kitchen vinyl, VCT vinyl tiles, cushion vinyl, and rubber tiles. Well, that’s basically it from us on gluing down a bamboo floor. Why not let us know your thoughts in the comments section below?