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All About the Different Types of Plywood

Learn how to choose the right type of plywood or other wood-based board for your home improvement project.

Excerpted from Do It Yourself Home Improvement

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Wood-Based Sheets

Wood is the main constituent of many sheet goods. Some of these may be used in the main structural components of a house; others for decorative finishings.

Plywood
Thin layers of wood, with the grain of each layer at a right angle to that of the previous layer, form plywood. Each layer is bonded tightly to the next, creating a very strong structure, and thickness adds further strength. Some plywoods are available as marine plies, which are impregnated with water-repelling chemicals.

Other boards
Sheet materials such as MDF and particleboard are made from pieces of wood compressed together at high pressure. Water-resistant versions of these sheets are also available for use in areas where humidity may be high.

Cutting a Sheet

Using a handsaw
If the sheet is coated (with melamine, for example), mark the guide line on the side that will be visible and cut with this side facing upward. This is because the edge of the coating on the lower face will chip during cutting; this way, the chipped edges will be invisible. Score along the guide line on all sides of the sheet with a utility knife, and use a fine-toothed panel saw to reduce the chances of chipped edges.

Using a power saw
The blade cuts as it rises, so to avoid chipped edges on the visible side of a coated sheet, mark the guide line on the rear of the sheet and cut with the rear side facing upward.

Cutting drywall
To cut a straight line in a sheet of drywall, place a straight edge along the guide line, and score along it with a utility knife. Fold the sheet to snap it along the line, and cut through the paper backing.

Types of Plywood and Other Boards

Plywoods

3-ply and 5-ply
These common types of plywood get their name from their number of layers: e.g, 3-ply has three layers. Uses include: Boxing in or decorative internal uses

Multi-ply
This is composed of many layers. Uses include: Heavyweight construction, e.g., house framing

Other Boards

Blockboard
Not technically a ply, but shares its characteristics. Has two thinner outer layers that enclose thicker, square-cut lengths of wood. It is therefore stiff and durable. May have a decorative veneer or a finish of a lesser grade of wood. Uses include: Ideal for shelves and cabinets, and can be finished with paint

Medium-density fiberboard (MDF)
Very versatile. Made up of highly compressed wooden fibers glued together. This method of manufacturing means that cut edges are neater than those on other materials. It can provide a rigid structural component, or can be intricately shaped to form a decorative surface ready for paint. Available in various thicknesses. Main drawback is that it gives off a very fine dust when cut, which must not be inhaled. Wear a mask when MDF is being cut. Uses include: Cabinets, cabinet doors, boxing in, shelving

Moisture-resistant MDF
A version of MDF that can resist moisture attack. It is often green. Uses include: Areas prone to moisture: e.g., kitchen or bathroom

Fiberboard
A lightweight version of MDF. Joints between sheets can be taped, and the boards painted. Uses include: Underlay for flooring, or as an alternative to drywall on a ceiling

Particleboard
Central core is composed of small wooden fibers. Has no decorative quality, so is usually covered. Some sheets fit together using a tongue-and-groove mechanism. Available in various thicknesses. Uses include: Often used as floor sheathing

Moisture-resistant particleboard
More water-resistant than normal particleboard. It is often colored green. Uses include: Flooring

Veneered particleboard
Has a melamine (plastic) or decorative wooden veneer. Uses include: Commonly used for shelves

Hardboard
Thin, compressed fiberboard. Standard hardboard has one smooth side, and one rougher side. Different grades and a variety of finishes are available. Uses include: Often used for parts of kitchen cabinets with a melamine (plastic) surface or veneer

Courtesy of © 2007 Dorling Kindersley Limited

Excerpted from Do It Yourself Home Improvement

© Dorling Kindersley Limited 2009

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