The following information is to help you familiarize yourself with the Technical Aspects of our Trade which relate specifically to installation and moisture. If you do have further inquiries, please feel free to contact our professional consultants.
Specifically the information here is provided to help familiarize builders & architects with the unique issues related to moisture and the installation of hardwood flooring.
When BC Hardwood Floor Co. Ltd. installs your floor in your home, we will ensure that all aspects of the installation are done right, from the start. We take careful consideration and measure moisture levels so that you will enjoy your wood floors now, and for a lifetime.
Yes. See our page about Radiant Heated Floors.
If installing over a crawl space, a layer of 6 – 8 mil plastic should cover the entire ground area. A vapor barrier laid between the hardwood and plywood is not enough to prevent moisture reaching the hardwood. The crawl space should be heated to the same temperature as the living space.
Open vents must be installed to provide adequate air flow. Hardwood flooring products vary – some are stable in this situation, some may not be usable. At BC Hardwood, our wood experts can help you choose the best solution.
Above grade: No restrictions
On grade: Solid wood flooring, Laminated (engineered) glue-down and floating.
Below Grade: we recommend engineered glue-down or engineered floating floors.
Consider the type of covering material you use as protection while other trades work on the floor. Be especially aware of radiant heat. Any thick protective covering, such as plywood or Gyproc, will insulate the floor, causing it to overheat. The resulting damage can be difficult and expensive to repair.
Pre-finished floors can be damaged beyond repair in these conditions. Builders paper, laid throughout the hardwood areas, is recommended. DO NOT tape the paper to fresh finish, as you may damage the finish. Overlap the seams and tape the paper to itself. Always cover the floor wall to wall.
Hardwood flooring should be delivered to site kiln dried at between 6 and 8% moisture content. Your subfloor should be within 4% moisture content of the hardwood flooring. Plywood is usually at 12% when purchased from a warehouse that protects its inventory from the elements (Always check that the plywood you are buying is dry). If for example you install the Hardwood Flooring at 8% moisture content over a plywood subfloor that is 14% it is likely that the hardwood will cup (see diagram below).
The diagram shows moisture migrating through plywood and into hardwood. The hardwood swells at the bottom first which changes the shape of the boards (cupping). Moisture can be removed by drying the surrounding environment and allowing the flooring a chance to flatten out. Only when the plywood, hardwood and surrounding spaces test dry should sanding be considered.
It does not take much moisture to make the floor cup significantly, for example: If you hold the prongs of a moisture meter to the skin of your hand the meter will register approximately 28% (Remember, with hardwood at 8% and plywood at 14% the floor will cup).
Sleepers are subject to the same rules. Concrete must also be tested to confirm the slab’s moisture levels are within 4% of the Hardwood Flooring. Concrete dries, under good drying conditions, at an approximate rate of 1″ per month (no radiant heat). If the slab is 4″ , or more, thick the dry time will slow down.
Numbers mentioned are approximate and may vary from site to site. This information is a guideline only.
Moisture from drywall mudding, painting, wet sheathing and wet studs etc. will always migrate to drier materials. For example, from an unheated crawl space, moisture will quickly absorb into dryer plywood, pass through it and occupy the next driest material which is usually hardwood.
The hardwood will be the first, and likely the only, material to visually show the signs of migrating moisture. The best way to tackle moisture problems is to plan ahead and take the necessary precautions and tests to ensure the correct site conditions exist before flooring is delivered to site. Testing accurately for moisture can only be done using good quality testing equipment.
Moisture problems are not easy to rectify and in many cases the best solution is to do nothing and allow the floor to settle naturally. The best way to tackle moisture problems is to plan ahead and take the necessary precautions and tests to ensure the correct site conditions exist before flooring is delivered to site. Testing accurately for moisture can only be done using good quality testing equipment.
For example: The central heating system in the home should always be on two weeks prior to delivery of flooring material. Heat should remain on at 20 degrees celsius throughout the installation and sanding process.
- Seal off the wet area.
- Use electrical heat. (not propane heat)
- Use low level air blowers.
- Use dehumidifiers.