Comparing Installation Methods: Glue-Down Engineer or Solid
When installing hardwood floors, you have two main options – engineered hardwood or solid hardwood. The installation method can also vary significantly, with the main methods being floating, nail-down, or glue-down.
Choosing the right hardwood and installation method is crucial to ensure durability, stability, and the look you want for your home. This guide will compare the pros and cons of glue-down installation between engineered and solid hardwood.
What is Engineered Hardwood?
Engineered hardwood flooring has become increasingly popular in recent years due to its versatility and stability. Engineered hardwood consists of multiple layers of wood pressed together in a cross-grain configuration. The top layer is high-quality hardwood, while the subsequent layers are often plywood or softwoods.Here are some key benefits of engineered hardwood:
More Stable
The layered construction of engineered hardwood makes it more resistant to expansion and contraction due to changes in temperature and humidity. This added stability makes it ideal for glue-down installation on concrete or over radiant heating systems.
Can Be Installed on Concrete
Since engineered hardwood is dimensionally stable, it can be installed directly on concrete slabs using glue-down installation. Solid wood should never be installed directly over concrete.
Lower Cost
Engineered woods tend to use less high-quality hardwood, so they can be lower cost than solid woods. The layered construction allows you to achieve the look of solid hardwood at a lower price point.
What is Solid Hardwood?
Solid hardwood flooring contains planks milled entirely from a single piece of hardwood lumber. Oak, maple, cherry, and hickory are common species used.Here are some benefits of solid hardwood:
Can Be Sanded and Refinished
The solid wood construction allows solid hardwood floors to be sanded and refinished repeatedly over time. This ability to refinish means you can maintain the floor for several decades or even centuries.
All Natural Material
Solid hardwood contains no manufactured materials or layers. This gives many homeowners peace of mind and meets their desire for using all natural flooring materials.
Rich, Distinctive Look
The grain patterns and color variations possible with solid woods create a warm, distinctive look that engineered wood cannot quite replicate. Exotic species like Brazilian cherry have stunning visual appeal.
Glue-Down Installation Method
Now that we have covered both engineered and solid hardwood as flooring materials, let’s compare using the glue-down installation method with each option.
How Glue-Down Installation Works
During glue-down installation, the hardwood planks are glued directly to the subfloor using an adhesive like urethane. The planks sit on top of the glue and are not nailed or stapled. Clamps may be used to ensure full contact while the glue dries.
Benefits of Glue-Down Installation
There are several benefits that make glue-down a popular installation method for both engineered and solid hardwood:
Creates Smooth, Even Surface – With no nails, a glue-down floor feels smooth and even underfoot. This makes it comfortable for walking barefoot.
No Squeaking or Creaking – The lack of nails also prevents squeaking and creaking noises which can happen as subfloors shift slightly over time. This allows for quieter floors.
Can Adhere Directly to Concrete – Glue-down installation adheres directly to concrete slabs, which expands flooring options for concrete level surfaces.
Allows for Irregular Layouts – Without nailing requirements, planks can be laid in varied directions to create custom layouts. Curved designs are also possible.
Better Moisture Resistance – Glue forms a tight bond with the subfloor which prevents moisture from seeping underneath the flooring. This improves water resistance compared to floating floors.
Now let’s compare the specifics of using engineered vs. solid wood in glue-down installation.
Glue-Down with Engineered Hardwood
Engineered hardwood is an excellent choice for glue-down installation. Since engineered wood is dimensionally stable, it resists expansion and contraction which could otherwise cause buckling or gapping. The layered construction and cross-grain orientation make it ideal for gluing directly to the subfloor.
Here are some benefits of choosing engineered hardwood for glue-down installation:
Can Be Installed Directly on Concrete – Thanks to its stability, engineered hardwood can adhere directly to concrete slabs in basements, garages, or on concrete substrates on upper levels. This expands flooring options.
Easier Installation on Radiant Heat Systems – The dimensional stability of engineered hardwood allows it to be glued over radiant heating systems. This is the recommended method for adding hardwood floors over radiant heat.
Prevents Buckling and Gapping Issues – Engineered wood resists moisture absorption far better than solid wood. This means the floor is less likely to exhibit gapping or buckling issues during seasonal humidity changes.
Thinner Overall Profile – Since engineered woods tend to be thinner than solid woods, the thinner profile can make it easier to meet transition heights and clearance requirements.
In nearly all cases, glue-down installation allows engineered hardwood floors to be installed with ease. It pairs nicely with the engineered construction method.
Glue-Down with Solid Hardwood
Gluing down solid hardwood is more complex than engineered wood. The solid wood’s sensitivity to moisture and expansion means special considerations must be made during installation.
When working with solid hardwood and glue-down installation, keep these guidelines in mind:
Not Recommended for Concrete Subfloor – Solid wood should never be glued directly to concrete slabs. Even with moisture barriers, the moisture penetration can damage the wood over time.
Only Use Below Grade with Careful Moisture Testing – Gluing solid hardwood below grade is risky. Careful moisture testing must be performed and precautions taken to prevent moisture damage.
Climate Control is Crucial – The space should have HVAC operating to ensure normal living conditions during the acclimation and installation period. Humidity levels in the space must be maintained year-round.
Leave Proper Expansion Gaps – Allow a 1/2” gap between the floor perimeter and walls or vertical objects to allow natural expansion and contraction which will still occur.
Use Proper Moisture Barriers – On wooden subfloors, use aquabar coating or rosin paper to create a moisture barrier between the subfloor and solid hardwood.
If you take appropriate precautions by selecting the right environment and allowing for natural wood movement, solid hardwood can work well with glue-down installation. But extra care must be taken compared to engineered wood.
Tips for Glue-Down Installation Success
Follow these top tips when installing engineered or solid hardwood using the glue-down method:
Acclimate the Flooring – Let the flooring adjust to living conditions by leaving boxes open in the installation rooms for 72+ hours beforehand. This prevents excessive expansion or contraction later on.
Moisture Test Subfloors – Use a moisture meter on concrete and an moisture probe on wood subfloors to verify safe moisture levels before installation.
Select Quality Adhesive – Choose a flexible urethane flooring adhesive formulated for hardness and moisture resistance once cured. Follow all label instructions.
Use Proper Trowel Size – Match the trowel notch size to the flooring thickness for correct adhesive spread rate. Too little glue can cause bonding issues.
Work Clean – Wipe excess adhesive from floor surface during installation using the adhesive manufacturer’s recommended cleaner. Adhesive can mar finish.
Roll Entire Floor – Roll the entire floor thoroughly using a 75-100 lbs roller within 60 minutes of installation to ensure proper adhesive transfer.
Follow these tips closely on your next glue-down hardwood flooring project for flawless results!
Glue-Down Engineered vs. Solid Hardwood Comparison Chart
Here is a helpful comparison chart summarizing the key differences between installing engineered hardwood vs. solid hardwood with the glue-down method:
| Engineered Hardwood | Solid Hardwood |
|---|---|
| Dimensional stability makes it ideal for gluing | Prone to expansion/contraction, requires precautions |
| Can be glued directly onto concrete | Should not be glued directly to concrete |
| Prevents most gapping and buckling | Still exhibits some natural gapping and expansion |
| Thinner profile easier to install | Thicker planks use more adhesive |
| Compatible with radiant heat systems | Not recommended over radiant heat |
| Lower risk of moisture related damage | Sensitive to moisture, higher damage risk |
| Overall easier, lower risk installation | Requires strict adherence to precautions |
Glue-Down Installation FAQs
Q: Can any wood species be used with glue-down installation?
A: Most domestic and exotic species work well, but bamboo and Brazilian cherry should be avoided for glue-down. Bamboo lacks the density to adhere properly, while Brazilian cherry expands and contracts too much.
Q: What thickness of engineered flooring should be used for glue-down installation?
A: We recommend using engineered planks that are 3/8” thick or thinner to allow the adhesive’s strength to penetrate through enough layers. This prevents any layer delamination issues long-term.
Q: Do I need to use moisture barriers with glue-down on concrete?
A: Yes, you need vapor barrier like 6 mil polyethylene sheeting between concrete and engineered hardwood. This prevents moisture passing between the concrete substrate and wood layers.
Q: Can I walk on the floor immediately after glue-down installation?
A: No. You must avoid walking on the floor for at least 24 hours after installation to allow adhesive to fully cure. Follow the adhesive manufacturer’s recommendations.
Q: How long does glue-down hardwood flooring last?
A: When properly installed and cared for, you can expect approximately 40 years of life from an engineered wood floor glued to the subfloor. Solid woods may last over 100 years.
Conclusion
Glue-down installation allows beautiful hardwood floors to be installed without noisy nails or staples. Engineered hardwood pairs especially well with glue-down thanks to its dimensional stability and layered construction. It glues down easily, even directly onto concrete.
Solid wood can also be glued, but care must be taken to test moisture levels and allow for natural expansion and contraction in the floor. Follow the recommendations in this guide to choose the right hardwood for your glue-down project and ensure lasting quality results.
