Many DIYers have trouble gluing pressure-treated wood. The problem is that some don’t know how to use a specific type of wood glue for gluing treated lumber.
If you’re not careful, you could end up with a mess and waste $100 on materials. Not to mention the hours spent trying to fix the mess.
That’s why we made this handy post so you can save time and money by gluing pressure treated wood the right way.
We’ll walk you through how to glue pressure-treated wood, the best glue for treated lumber, and how to avoid mistakes.
Let’s dive in.
Can You Glue Pressure Treated Wood?
Yes, you can glue pressure-treated wood together. However, since most pressure-treated woods are used for outdoor projects, you need to use special glue to withstand dry and moist conditions without breaking apart. Some of the best wood glue options to consider are polyurethane and yellow glue.
How To Glue Pressure Treated Wood
You are aware the treated wood you plan to glue together contains chemical preservatives: waterborne treatments and oil-type preservatives. These preservatives are forced into the wood grain during the pressure treatment process.
The chemicals used during the pressure treatment process can make the wood damp and hence difficult for the glue to adhere to. Although pretreatment may make gluing difficult, it doesn’t make it impossible.
Ensure you have the following tools and materials with you before you begin. Afterward, follow the steps below to prepare the wood and glue pressure-treated lumber the right way.
Interesting Read: How to Join Two Pieces of Wood at 45 Degrees
Tools and Materials
- Dust mask or respirator
- Clean rag
- Shop vacuum
- Tack cloth
- Mild dish soap
Gluing Pressure Treated Wood- Steps
Step 1: Preparation
Thorough preparation guarantees the success of your project. Considering that we’re dealing with pressure-treated wood, begin by wearing a dust mask and heavy-duty gloves.
It may seem obvious but, ensure you’re working in a well-ventilated space, if not outdoors.
1. Clean the wood
This step is crucial for ensuring there is no debris or contaminants lingering on the surface. Cleaning both dry and damp treated wood also ensures the glue will adhere well to the treated surface.
Mix mild dish soap in a bucket of water. Dip a clean rag in the soapy water and gently clean the wood surface. Repeat the process until the rag comes off clean when you run it on the surface.
2. Allow it dry
How long does wood glue take to dry? Well, set the cleaned wood on a dry location and let it air dry for about 24 hours (or more).
If you plan to use polyurethane adhesives, you can skip the drying time. This is because Polyurethane is a water-based adhesive. This means it adheres well to a damp surface and cures in the presence of moisture.
However, if you’ll be using other types of glue, ensure the treated wood is dry before you proceed to the next stage of wood prep.
You could speed up the drying time by placing the wood under the sun if possible or using a dehumidifier if there’s not much sun in your region.
3. Plane or sand any unevenness
Once the treated lumber has sufficiently dried or if you choose to work with a plank of damp wood, run it through a plane to even out any bumpy knots and grain marks.
Alternatively, you can consider sanding the surface using medium grit sandpaper and finishing with finer grit sandpaper. Only focus on the part you intend to glue.
Remember to only sand or plane lightly to expose a fresh and smooth surface ready to take in the adhesive. Remember, over sanding or planing might strip the protective chemical layer on the surface of the treated lumber.
4. Clean the dust off
Since pressure-treated wood contains toxic chemicals, collect the dust and dispose of them in a landfill. Using a shop vacuum is a surer way to ensure that no grain of dust is left lying around.
Finish cleaning by running a damp rag or tack cloth on the sanded surface: gluing needs a clean and smooth surface.
Step 2: Apply the glue
Squeeze out the glue on one part of the prepared wood surface. Since there’s no correct way to apply glue, you can apply glue in circular, zigzag, or long straight lines.
Step 3: Spread the glue and attach the two pieces of treated wood
There are two ways to do this: rub the two pieces of wood against each other or spread the glue using a roller or brayer.
If you’re gluing smaller pieces of wood together, it makes sense to rub them together. However, if you’re gluing larger pieces of treated lumber, it’s probably best to use a roller or anything you can improvise with.
Whichever means works for you, ensure the glue covers every inch of the treated wood surface. Then place and press the pieces of treated lumber together.
Step 4: Clamp the glued pieces
You need to hold the glued lumber together while the glue cures: this is meant to enhance bonding. Ensure that the glued pieces are aligned before clamping.
You can use any suitable clamps available to you and suitable for the size of your glued pressure-treated lumber.
Step 5: Remove the excess glue squeezed out
Once you have securely clamped the glued pieces, there’s a chance you’ll notice excess glue squeezed out. You can easily wipe it out using a damp rag while the glue is still fresh.
However, if the glue dries before you can wipe it off, use a plastic scraper to peel off the excess dried glue.
Step 6: Allow the bond to dry for maximum strength
At this stage, your work is done. Most glue should be able to dry solid in less than 24 hours. Let the wood dry for that long or even longer if you’re not in a rush with your projects. Use these steps if you are gluing green treated plywood.
What Type of Glue Works Best For Pressure Treated Wood?
There are several epoxy adhesives designed to function in dry and moist conditions.
However, when you are gluing pressure-treated lumber, you need to work with a type of glue that’s waterproof. This guarantees it won’t fall apart on different environmental exposure conditions. Resin glue is your best bet here.
Resorcinol glues are the only adhesives with complete waterproof glue lines on wood. Urea resin glues and polyvinyl resin adhesives can guarantee a modestly water-proof bond between the glued surfaces.
Also, there’re some construction adhesives that offer reliable resistance to the high moisture content in the wood. These adhesives often withstand lower temperatures than regular wood glues.
Below are some of the best glues you can use when gluing treated lumber.
Polyurethane glue is the first choice on our list. This adhesive is water-resistant and, therefore, perfect for use on outdoor applications.
This adhesive is an excellent choice if you’re gluing pressure-treated wood since they are mostly damp. After all, polyurethane glue cures in a damp environment.
However, if you decide to use Polyurethane glue on fully dried or kiln-dried treated lumber, you may have to dampen the surface material first for the glue to adhere well and form high-strength bonds.
Polyurethane adhesive also handles porous end grain perfectly. One of the most common brands producing this type of glue is the Gorilla glue.
Titebond Polyurethane glue is another water-resistant wood glue known for its strong initial tack that can be used with pressure-treated wood. However, the waterproof feature is only realized when the glue is completely dry.
Use Titebond III glue on kiln-dried pressure-treated lumber to get a perfect bond between the glued pieces. These glued pieces would be great for constructing outdoor furniture, cutting boards, etc.
- Titebond III Wood Glue Quart 32 Oz
- Waterproof formula that cleans up with water
- Longer open assembly time
Also, this adhesive has an open time of about ten minutes before it dries, which means you can easily clean the excess glue with water while it’s still wet. However, if it dries out, you can sand it down. Titebond III is also the best if you want to glue mdf together.
Yellow glue is widely known as the carpenter’s glue. This adhesive is an aliphatic resin of the PVA family. It’s usually perfect for everyday glue-ups for projects such as cabinets and or furniture pieces.
- Great for carpentry and home repairs
- Clean up soap and water when glue is wet scrape & sand when glue is dry
- 4 Oz Bottle
This glue is best used on dried surfaces; therefore, ensure your pt wood is properly dried. If not, the structure will slide and fall off.
Yellow glue is known to form a stronger bond than the wood itself when it dries, which is the guarantee you need for your outdoor projects. It also doesn’t leave a visible glue line, so your readily glued pieces won’t have a distracting visible line.
You also get a chance to clean up yellow glue with water while it’s still dry. But, you can also sand it smooth if the excess dries.
This adhesive is another excellent option to consider using on treated wood. Cyanoacrylate glue bonds quickly to wooden surfaces. Besides, this glue comes in two viscosities: watery and jelly thick.
This variety allows you to choose whichever works best for your project. For example, the watery Cryanoacrylate glue is excellent for reinforcing punky wood. On the other hand, the jelly-thick Cryanoacrylate glue is your best bet when filling gaps in the wood.
- GEL FORMULA: No run control gel formula that is great for use on vertical surfaces
- ANTI CLOG CAP: Helps keep the glue from drying out. It's Gorilla tough use after use.
- IMPACT TOUGH: Specially formulated for increased impact resistance and strength
The only downside to this glue is that it’s brittle. This means it won’t hold up well if used in places with high traffic.
Out of the four best types of glue to use with pressure-treated lumber, Polyurethane glue stands out as the only one that can be used with damp-treated lumber. The other three adhesives require a completely dry surface for best results.
Generally, you can’t go wrong with any of these adhesives. If the gluing doesn’t sit right, here’s how you can remove glue from wood
What Else Can I Use to Join Pressure Treated Lumber?
Gluing treated lumber is only one way of joining them together. That said, other methods are equally effective at putting together pressure-treated wood.
Most producers of pressure-treated lumber often use stainless steel to join treated lumber. Other alternatives you can use for this purpose are; screws, galvanized nails, connectors, bolts, and anchors.
Be sure you use stainless steel because regular steel will fall off prematurely due to the chemical reaction with preservatives in the treated wood.
You could also try and drill through the center of the treated lumber boards. Next, run a couple of threaded rods through the drilled wood when you join them together.
Whichever method you choose to join your pt lumber depends entirely on the amount of security you want your joint to have and the intended function of your structure.
Are you looking to join two pieces of wood lengthwise? Read to find out how.
What are the Challenges of Gluing Pressure-Treated Wood Together?
Pressure-treated wood has chemical deposits on the surface. These are meant to seal the wood from external damage. These deposits may make it difficult for the glue to adhere to the surface.
Pressure-treated wood with waterborne chemicals are mostly damp when freshly produced. Yet, for them to be glued, you need to have polyurethane glue. But, in the absence of waterborne glue, you might wait for several months before the wood is dry enough to be glued.
Just like gluing stained wood, preparing the pressure-treated lumber for gluing involves a degree of sanding or planing. While this step is critical, you risk inhaling the toxic dust or exposing the treated wood to excess moisture that could damage it.
If you happen to have the wood treated with oil-type preservatives, such wood cannot take in glue. This is because such treated wood usually has high retention of heavy solvents like pentachlorophenol or creosote.
Can You Use Liquid Nails On Pressure Treated Wood?
Yes, you can use liquid nails to join pressure-treated wood together. However, in most cases, liquid nails dry out over time and tend to lose their adhesive strength. In my opinion, use liquid nails on pressure-treated wood structures that do not get heavy use.
Related Post: Liquid Nail Vs Wood Glue
Do you recommend gorilla wood glue for pressure-treated lumber?
Gorilla glue is a waterproof adhesive. It’s strong enough to be used with pressure-treated lumber for outdoor projects. Gorilla glue works to form an unbreakable bond that can withstand the elements.
Does Titebond 3 work on pressure-treated wood?
Titebond III works best on fully dried pressure-treated wood. This adhesive is water-based and therefore adheres better to a dry surface. If you use it on “wet” treated wood, the moisture content will prevent it from drying to its maximum strength: rendering it a complete fail.
Can you glue treated wood to concrete?
Yes, you can glue treated wood to concrete. Whether the soil extends above the wood or goes below it, opt for the gluing method when tubing or sticking heating glues in concrete where screws and nails are impractical.
Best construction adhesive for pressure-treated wood
Polyurethane glue is hands-down the best construction adhesive for gluing pressure-treated lumber. This glue cures in a damp environment: which is the main characteristic of pressure-treated wood. Also, this glue’s waterproof characteristic makes it an excellent choice for outdoor projects.
Gluing pressure treated wood the right way has never been easier! Knowing what you will need, the steps to follow, and the best glue to use for gluing pressure-treated lumber, nothing stands in your way of constructing weatherproof outdoor structures. Remember the challenges of gluing pressure-treated wood to inform you of what you could encounter and help you choose treated lumber that can take in adhesives.
Do you have any tips you’d like to share? Engage us in the comments section below.
What to do Next
Be sure to check out our post on when to stain pressure treated wood to avoid any blunders of staining too soon.