コンクリートスラブは下地材を設置できる状態ですか?

Choosing the right underlayment and installing it correctly can make or break a flooring project. Doing it right starts with making sure the concrete slab is ready.

Underlayment is a broad topic. To keep it simple, this article doesn’t cover installation over wood subfloors and gives only a few examples of underlayments and their uses. Also, the terms “underlayment” and “subfloor” are sometimes used interchangeably in the flooring industry.

この記事で「下地材」とは常にコンクリート床下地と床仕上げ材（表層）の間にある層を指します。

下地材の例

Underlayment serves many purposes, from protecting the floor covering from moisture and movement in the concrete subfloor to meeting sound insulation requirements in multi-story buildings. Floor covering manufacturers usually specify any underlayment their products require.

Always check the floor covering manufacturer’s specifications and warranty to make sure the underlayment you choose is approved for that product.

フローリング

For wood flooring installed over concrete, the National Wood Flooring Association (NWFA) recommends an “impermeable vapor retarder with a perm rating of less than or equal to 0.15.” Examples include 6-mil construction-grade polyethylene film, double felt, chemical retarders, or a urethane membrane.

詳細については、NWFAインストールガイドラインを参照してください。これは、次のURLから購入できます。 www.nwfa.org.

For glue-down and floating floors, you may need a pourable, self-leveling underlayment to correct minor imperfections in the slab surface.

For floating wood floors, manufacturers sometimes recommend padded underlayment. Its smooth surface lets the planks move as they expand and contract with seasonal humidity changes. Padded underlayment can also help reduce footfall noise and add thermal insulation. Examples include felt, foam, rubber, cork, and rubber-cork rolled goods. Some padded underlayments for wood floors include a vapor retarder layer.

セラミック、磁器、石タイル

For tile, leveling the concrete floor is critical. “Lippage,” or height differences between adjoining tiles, can damage tile and even create safety issues. Mortar beds were the preferred leveling underlayment for tile for many years, but pourable, self-leveling underlayments are now more common because of construction time constraints.

カーペット

As with other floor coverings, you may need a pourable, self-leveling underlayment to level and finish the slab surface. A carpet pad may also be required. Padding can provide cushioning, noise reduction, and thermal insulation.

ノイズリダクション

In multi-story buildings, you may need acoustic underlayment, sound-absorbing carpet padding, or other products to reduce impact noise, such as footsteps, and airborne noise, such as voices and music.

コンクリートスラブの準備

Before installing underlayment, make sure the concrete slab is clean, free of contaminants, and dry.

コンクリートの水分検査

確かに コンクリートスラブは乾燥している enough, first check the underlayment and floor covering manufacturers’ specifications for their concrete moisture limits.

Then test to make sure the slab’s moisture doesn’t exceed those limits. Manufacturers usually give limits for both moisture vapor emission rate (MVER) testing and in-situ relative humidity (RH) testing.

The MVER method, also called calcium chloride (CaCl) testing, has been used in the United States for a long time. But more and more flooring professionals now prefer in-situ RH testing.

MVER testing measures only the moisture near the surface of the slab before the flooring is installed. In-situ RH testing measures moisture within the slab, which moves toward the surface and stays there once a low-permeability floor covering is installed.

That’s why many flooring experts consider in-situ RH testing a better way to tell whether excess moisture in the slab could cause the flooring to fail.

In-Situ RH Testing Tools

The recognized standard for in-situ RH testing is ASTM F2170, and many floor covering and underlayment manufacturers now require F2170-compliant testing. You can buy a copy of the standard at store.astm.org.

When choosing an in-situ RH testing product, look for a complete reading, recording, and reporting system designed to follow ASTM F2170. For example, you’ll need probes that measure RH and temperature at each test site and an instrument that measures the ambient temperature and RH in the room.

ASTM F2170 calls for three tests for the first 1,000 square feet and at least one more test for each additional 1,000 square feet. You also need to record ambient temperature and RH during testing. An ambient monitor also helps you confirm that the slab and the space above it have been at service conditions for at least 48 hours before testing, as the standard requires.

The product should include probes and extenders that make it easy to install them at the correct depth. Per ASTM F2170, that’s スラブの厚さの40% for a slab drying from one side and 両面乾燥のスラブの場合20％.

It should also include accessories that make it easy to thoroughly clean each drilled hole, since leftover dust can cause false readings.

ASTM F2170 requires each probe’s calibration to be checked within 30 days before use. The easiest way to meet this requirement is with single-use probes that come with calibration certificates from the manufacturer.

When selecting an in-situ RH testing product, think about how easy it will be to take readings and meet the ASTM F2170 reporting requirements. Look for a product that records and stores test-site and ambient readings while you’re away from the job site.

Better yet, choose one that sends the data directly to your mobile device when you return to the job site, with free mobile apps that make reports easy to create. A system with these features makes recording and reporting faster, more accurate, and more secure.

How can you be sure the slab is dry enough to install underlayment? Confirm the maximum moisture limit for the flooring system, and follow ASTM F2170 for in-situ RH testing when applicable. The easiest way to do that is to choose a testing system designed specifically to meet the standard.

詳細については、下記までお電話ください。 (541) 291-5123.

Rapid RH を購入

最終更新日: 8 年 2026 月 XNUMX 日