Thursday, May 28, 2015

Working with Concrete Sub-Floors and Luan Underlayment

Dusty concrete slabs may be primed with one coat of S-185 Primer. Sweep
or vacuum the concrete and apply the S-185 with a 3/8″ nap paint roller.

You may also prime concrete subfloors with the recommended flooring
adhesive before installing luan plywood. After sweeping/vacuuming,
apply the adhesive using a smooth-edge trowel, then apply plywood over concrete.
 When using adhesive as a primer, allow the adhesive to dry completely before
installing luan plywood.

After drying, install the flooring in accordance with the recommended installation system. NOTE:
A dusty concrete floor on-grade or below-grade may be a sign of alkali salts.
A rough concrete floor can be ground smooth with a commercial
diamond or carbide-equipped grinding machine. If the concrete subfloor
is extremely rough or uneven, it may be too great a job to smooth this
way. In this case, apply a cementitious underlayment such as S-183, S-184
or S-194. A smooth, flat, uniform surface is necessary as a good base for
resilient flooring.

Gyp-Crete 2000®/3.2K Data Sheet - MAXXON

Product Description: Gyp-Crete 2000®/3.2K by Maxxon is a gypsum floor underlayment is engineered to deliver compressive strengths up to 3,200 psi (22.1 MPa), also delivering enhanced resistance to surface abrasions and even faster drying time.

 It's ideal for use over wood or concrete subfloors in single family, light commercial, and multifamily construction, as well as renovation projects. Its crack-resistant surface provides a perfect base for practically any floor covering. Now always a "green" building material, Gyp-Crete 2000/3.2K is an ideal gypsum floor underlayment for sustainable building projects.


On Grade Concrete Flooring and Luan Plywood Underlayment

On-Grade Concrete Floors and Luan Plywood Underlayment

 a. The slab must be of good quality, standard density concrete with low water/cement ratios consistent with placing and finishing requirements, having a maximum slump of 4″, a minimum compressive strength of 3500 psi, and following the recommendations of ACI Standard 302.1R for class 2 or class 4 floors and the Portland Cement Association’s recommendations for slabs on ground.


b. The concrete slab must be dry, clean, smooth, structurally sound and free of foreign materials that might prevent adhesive bond as described in ASTM F-710, “Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring”.


 c. The concrete slab must be protected from ground moisture with an effective and intact vapor retarder that conforms to the requirements of ASTM E-1745, “Standard Specification for Water Vapor Retarders Used in Contact with Soil or Granular Fill Under Concrete Slabs.”


d. The concrete slab must be placed directly on the vapor retarder.


e. The concrete must be wet cured with a moisture-retaining curing cover. Do not use spray-on curing compounds because these reduce the drying rate of concrete and can interfere with adhesive bond.


f. Before installation of the finished flooring, moisture, alkali and bond testing must be conducted.


 1) Moisture testing must be performed in accordance with ASTM F-2170 “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes” (preferred method) or in accordance with ASTM F-1869, “Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride.” See the section on Moisture Testing for more details.

2) The surface of the concrete must have a pH of 9 or less. 3) Bond testing must be run to determine compatibility of the adhesives to the concrete slab.

Working With Below Grade Concrete Floors and Luan Plywood Underlayment


Below-Grade Concrete Floors and Luan Plywood Underlayment 


 The floor classification must be per the current edition of the American Concrete Institute’s “Guide for Floor and Slab Construction”, ACI 302.1R:

1) For residential and light commercial: Class 2 (except minimum compressive strength must be 3500 psi)

2) For commercial and institutional:

Class 4

b. Shall have a minimum compressive strength of 3500 psi.

c. Before installing Luan Plywood Underlayment over concrete slab, it must be dry, clean, smooth, structurally sound and free of foreign materials that might prevent adhesive bond

d. In addition to this the concrete slab must be sealed from ground moisture with an effective and strong vapor blocker/stopper


The concrete slab must be placed directly on the vapor retarder.

f. The concrete must be wet cured with a moisture-retaining curing cover. Do not use spray-on curing compounds because these reduce the drying rate of concrete and can interfere with adhesive bond.Chapter IV — Subfloors and Underlayments 55 g. Before installation of the finished flooring, moisture, alkali and bond testing must be conducted.

 1) Moisture testing must be performed in accordance with ASTM F-2170 “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes” (preferred method) or in accordance with ASTM F-1869, “Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride.” See the section on Moisture Testing for more details.


 2) The surface of the concrete must have a pH of 9 or less when tested according to the method described in ASTM F-710. 3) Bond testing must be performed to determine compatibility of the adhesives to the concrete slab.

Working With Concrete Subfloors and Luan Underlayment

Working With Concrete Subfloor and Luan Underlayment

New and existing concrete subfloors will have to reach or exceed the minimum requirements of the latest
edition of ASTM F 710

Introduction to the new requirements can be found here along with all relevant information.

“Standard Practice for Preparing Concrete Floors to
Receive Resilient Flooring” available from the American Society for Testing
and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428;
610-832-9500; http://www.astm.org.



Depending of the type of concrete used or which cement material used
as a base for resilient flooring, in the event of underlayment failure, the
responsibility for warranties and/or performance guarantees rests with
the concrete or cement-like material manufacturer and not with the
manufacturer of resilient flooring.


1. Concrete Floors and Moisture

As usual concrete subfloors can be a source of moisture-related flooring
failures, which sometimes include concrete subfloors themselves. By its very nature,
concrete starts as a water-saturated mass which must cure and then dry
sufficiently to allow the installation of flooring.

Above-grade floors normally have only the mix water to contend with although rain, spills and
water leaks can add more water. Roughly one-half of the mix water is
consumed by hydration of the cement during the curing period, with the
rest being slowly reduced by evaporation.

Once dry enough for installation, there is little chance of future moisture related problems on
above-grade concrete slabs when used with luan plywood flooring. Concrete floors-on-ground, or below ground, have not only the mix water to consume and dissipate, they also have a
potentially inexhaustible source of moisture from the ground as well as transfer to the underlayment regardless of type.

When covered with resilient flooring as well as luan underlayment, a concrete subflooring that has been constructed on top of thesubgrade soil will become approximately as moist as the soil on which
it was installed.

Tuesday, March 17, 2015

Luan Plywood Ceiling Installation


Luan Plywood Ceiling Installation 


Attaching will be with construction adhesive and nails. Depending on type luan  plywood you can go over studs directly or you may need to go over drywall if its thin like paneling. I saw this done once where the fasteners were incorporated into the design.

When you use black lag bolts with allen wrench sockets. Each panels had finished edges, painted black. Some panels were about 2'x3' if I recall correctly. and had about a 1.5" space between each.  They were shimmed down from a main ceiling by about 1.5".  main ceiling, or sub ceiling if you will, was also painted black.

Consider the panels were a pre-finished mahogany wood. It looked really neat. I considered doing this in my basement. There are also beadboard options, in sheets or boards, that look nice. Bottom line - This can be a real architectural feature or it can be a red flag when you go to sell, depending on how its done.

If you just want to take up luan plywood to cover some problem and avoid mudding thing you may be going down a wrong path. If you are doing it for design reasons then go for it and make it nice.




Using Luan Plywood as a Ceiling

Step 1 - Find the Ceiling Joists

Use the stud finder to locate all ceiling joists and mark the location with a pencil. Mark the joist by snapping a chalk line across the ceiling. The luan plywood will be installed perpendicular to the joists.

Step 2 -  Luan Plywood Installation

Glue the precut plywood in place using panel adhesive. Apply the adhesive to the luan plywood in a thin serpentine patterned line. Place luan  plywood on the ceiling pushing it against the edge. Use the pneumatic nail gun to put the luan plywood in place. Place the nails where you marked the ceiling joist.
Continue this process for each luan  plywood panel, using a rubber mallet to butt the panels as close together as possible.

Step 3 - Wood Molding

Place construction adhesive on the back of the precut wood molding. Align the molding with the edge of the ceiling. Use finishing nails to fasten it in place.

Step 4 - Sanding and Prep

Cover all nail holes with wood putty using a small putty knife. When the putty has completely dried, use sandpaper to smooth any imperfections in the wood and the putty. Use a soft cloth to remove any dust from sanding.