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Can You Put Hardwood Over Crawl Space? (How To)

Installing hardwood flooring over a crawl space is risky. The big enemy is dampness and moisture in the ground that can wick into the floorboards, causing them to either cup (edges curl inwards) or crown (edges curl upwards). Once the boards are warped, you will need to sand them to make them fit together again. If you use any laminated board flooring, you may need to replace the whole floor.

Generally, you can put a hardwood floor over a crawl space if your floor joists are at least 18 inches high to prevent moisture from the ground from wicking into the wood and warping the floorboards.

man fixing the wood floor

The humidity in the crawl space will change with the seasons. To protect your floor from moisture, you can install foundation vents, but these are not completely reliable to protect your floor from warping. You may also install a vapor barrier as an additional measure to stop the moisture, but again it may not be a sufficient precaution to control the amount of wetness your hardwood floor is exposed to.

Should You Put Hardwood Over Crawl Space?

man fixing the wood floor

Building a house is a big investment, and sometimes there is just not enough budget to build a full basement. Many homeowners opt to build over a crawl space to save costs. Of course, concrete is the best floor to put over a crawl space, but hardwood flooring has a natural appeal that many homeowners want.

When putting a hardwood floor over a crawl space, you must ensure you insulate it against moisture as much as possible. If you have a dirt floor in your crawl space, a 6mm plastic vapor barrier under the hardwood floor should keep it safe from moisture and bugs.

Many hardwood floors over the crawlspace fail because of failure to seal off the moisture rising from the subfloor.

To prevent damage to your floor, ensure that your crawlspace is at least 18 inches from the ground to the joists. Install adequate ventilation by using open perimeter ventilation or mechanical ventilation.

Seal off the ground with at least a 6mm thick polyethylene vapor barrier extending at least 8 inches up the walls. Use moisture-resistant tape to seal the joints, and make sure that the plastic strips overlap at least 6 inches. The vapor barrier can be covered with 3 inches of crushed stone or gravel to give access for work to be done in the space without tearing the plastic.

What Tools Do You Need To Put Hardwood Over Crawl Space?

tools for floor

The tools for laying hardwood flooring can be bought in most home improvement shops. The tools listed below are the most important ones to install the floorboards, but this is not an exhaustive list. The list will also vary whether you use nails to place individual planks or glue them down. A vapor lock adhesive is recommended to adhere to the floor as it is water-resistant and provides an additional layer of protection against moisture.

Copyright protected content owner: and was initially posted on January 4, 2023.

To install the hardwood flooring, you will need the following tools: a miter saw, circular saw, claw hammer and nail punch, straight edge, measuring tape, moisture meter, level and leveling compound, sandpaper, rubber mallet and tapping block, utility knife, power drill, finishing nails and more.

Also, remember to add personal protection equipment like earplugs, safety glasses, and a dust mask when working with wooden flooring.

What Preparations Do You Need To Install Hardwood Over Crawl Space?

man fixing the wood floor

To successfully install a hardwood floor, ensure the environment is as dry as possible. The building needs to be completely closed with all the doors and windows fitted. Before you start laying the floor, all the “wet” work should be completed, like plastering and painting. Don’t install hardwood floors in a bathroom, and check manufacturer’s instructions whether it can be installed over an in-floor radiant heat system.

When preparing for installation of the hardwood floor over the crawl space, you need to ensure it is thoroughly dry and well-ventilated, a plywood subfloor is installed, and all plastering and concrete work has been completed and cured. Exterior grading should be complete, with gutters in place.

The room should have an ambient temperature of at least 60-75 degrees Fahrenheit and a humidity level of 35-55 percent. Use a moisture meter to check the moisture content in the plywood subfloor before starting to lay the hardwood. If the moisture is more than 12%, delay floor laying and dry out the subfloor first.

Copyright article owner is for this article. This post was first published on January 4, 2023.

How To Install Hardwood Over Crawl Space

man fixing the wood floor

Before installing the hardwood, ensure that the subfloor is clean and dry (within moisture limits). Pick a starting wall, usually the straightest and longest wall in the room, to allow for a nice flow of planks.

Face nail the first row, making sure that the “tongue” faces away from the starting wall. Blind nail boards into place by drilling pilot holes in the plank, driving the nail and sinking the nail head below the surface.

When placing subsequent rows, ensure that the tongues and grooves fit well to prevent the boards from moving over time. Remember to leave ¾ inch gap along the end wall to accommodate any expansion of the floorboards.

To install a hardwood floor over a crawl space, follow these general guidelines: floorboards should be installed at 90 degrees to the joists, pick a starting wall, remove existing base moldings and floor coverings, and do not use pieces with obvious faults.  

Once you have covered the entire floor of the house or room with the flooring material, vacuum the boards and clean them with a soft cloth mop to remove all the dust and dirt. Reinstall all the moldings by nailing them into the wall, not the floor. You may need to cut the bottom of the doors to accommodate the flooring height to ensure they can open and close without dragging.

If you are facing a decision on whether can you put hardwood over crawl space? (how to) you can rest assured that it is possible to have a beautiful wooden floor in your home even though it is built over a crawl space. Provided that you invest time and money to prepare the foundations thoroughly to reduce as much as possible the amount of moisture in the crawlspace and install proper waterproofing measures, your floors should be safe.

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ReadyToDIY is the owner of this article. This post was published on January 4, 2023.

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