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Plastic wood! Those two words, until very recently, were not used in the same sentence unless you were talking about some sort of wood filler for nail holes. If you told an old carpenter that you're going to be building a plastic deck, you'd probably be laughed out of the shop. However, as the old saying goes, "times are a changing".

Concerns about our environment and the effects of thousands of tons of plastic ending up in disposal sites daily has increased our awareness of this growing problem. Companies, as well as the scientific community, are looking for ways to turn this waste into a re-usable resource. Canadian Plastic Lumber (CPL) is one of those companies who use waste plastic to manufacture a product called PLASBOARD, one of the many new "alternative to wood" building products that are helping to combat this potential environmental nightmare. CPL reported that they will " turn over 2,000,000 pounds of post consumer plastic waste into plastic lumber this year.

As a renovation and kitchen cabinetmaking contractor I'm always on the lookout for leading edge products. Recently, products such as the new wood "I" beams, house wrap materials, energy efficient widows, and innovations in kitchen cabinetmaking hardware have had an effect on how we build and design. Decking, up until a few years ago, meant using traditional wood products such as cedar or pressure treated spruce. Today more and more companies are investigating alternative products for decks, fences, and other outdoor structures. A natural fit is all the waste plastic that we discard. The problem is how to manufacture "wood" like material that is easy to use and cost effective to manufacture. More importantly of course, is the problem of consumer acceptance of a material that will replace wood.

Tony Verbik, of Canadian Plastic Lumber in Lindsay, Ontario, states that "consumer interest at trade shows and product fairs has been outstanding. Once consumers understand the added value of a building material that is maintenance free, won't splinter, split or rot and is easy to work with, they get excited about our product. We've put allot of effort into making our plastic lumber visually appealing as well as extremely practical and environmentally friendly".

Plasboard, according to the manufacturer's data sheet, is durable, maintenance free, comes in a variety of colours, is guaranteed not to rot, and is skid resistant especially when wet. Grey, green, and brown were the colours available when I purchased my Plasboard. However, I found quite a variance in each colour selection. My choice for the deck was brown and it ranged from dark to light brown to "brownish" grey.

Rick Adams, of Adams & Kennedy Ltd., who are a major distributor of this product in the Ottawa Valley, said that he is supplying two deck building contractors on a regular basis. Acceptance of the product is rapidly increasing and inquiries now come on a daily basis, according to Rick.

One of the major concerns with plastic lumber is the expansion and contraction properties. Because of this, a "floating" structure has to be built on a fixed structure. The expansion and contraction rate is stated as ".3% times the length of the product if temperature variations of 50 degrees centigrade are likely". Using the manufacturer's formula, and given our weather conditions, the maximum expansion and contraction of an eight foot board would be .29 inches or a little better than one quarter of an inch. Therefore a twelve foot wide deck could expand and contract about three eighths of an inch from the heat of summer to the cold of winter.

Plasboard, like wood, is available in many sizes suitable for deck construction. I used 2" x 2"'s which are actually 1 1/2" x 1 1/2", 2" x 4"'s which are 1 1/2" x 3 1/2", 1" x 6" boards which are 1" x 6", and 3" x 3" posts which are 3" x 3". The 3" x 3" posts were used as main posts for the railing and the 2" x 2"'s for the balusters. The 1" x 6" planks were used as deck boards as well as the deck skirt, railing cap, and stair treads. I understand that turned plastic spindles are also available from CPL however they were not in stock at the local dealers when I purchased my materials.

This product can be treated like wood in many ways. You can cut it ( use carbide tipped blades for best results) and drill it , but it cannot be used as a structural member. You must build your deck structure with traditional wood products. For this deck I used pressure treated spruce under the Plasboard. There are other special considerations when building with plastic lumber. Most important is the fact that the expansion and contraction factor has to be accounted for, particularly with deck boards. The structure supporting the deck boards, in my case the pressure treated 1" x 6"'s, must be built independent of the fixed structure. In effect, you must build a "floating structure" on the fixed supports that are anchored to the house and piers.

I built my fixed portion of the 12 foot wide by 22 foot long deck with double 2" x 8" lumber which formed four beams at approximately five foot centres. On top of those beams I bolted a 1" x 6" piece of Plasboard to isolate the upper portion of the deck. The Plasboard pieces were slotted and the bolts were left slightly loose to allow for the required three eighths of an inch expansion and contraction ratio over the twelve foot deck width. The floating portion of the structure was built with 2" x 6" joists of pressure treated spruce at twelve inch centres. Twelve inch on centre joist spacing is recommended for one inch Plasboard material and sixteen inch on centre joist spacing for one and a half inch decking planks. The floating joists were attached to the Plasboard shim only, with screws that were driven from under the Plasboard and into the 2" x 6" pressure treated joists. By installing the joists in this manner, the upper section of the deck structure was isolated or "floating" on the fixed portion and able to move as needed. It should also be noted that you do not install blocker or spacer boards between the joists. We need free movement of the joists to allow the Plasboard deck boards to expand and contract with weather changes. It is also important that the header boards at the end of the joists are Plasboard to allow movement of the joists as the expansion and contraction occurs.

Currently, Plasboard 1" x 6" boards are only available in eight and ten foot lengths. My deck being twelve feet wide required one eight foot and one four foot board. I alternated the butt joints on every second plank. To provide a stable and solid deck surface at the butt joint I doubled-up on the 2" x 6" joists at the four foot and eight foot mark. This meant two extra joists but I wanted a strong and long lasting deck surface.

I have built many decks over the last twenty years. However, building practises that I took for granted had to be reviewed because of the differences and oddities of this new plastic lumber. For one thing, joists must be in a perfect plane with each other. It is important in conventional lumber deck building, but critical with plastic lumber deck building. Lumber, particularly 2 x 6's, will push down or lift up on the odd joist that is slightly out of plane with the others. Plasboard, because of it's flexibility, will simply ride up and down across the joists and you end up with a "wavey" deck surface. I learned this the hard way.

There are a few other oddities with plastic lumber that you should be aware of before building. When installing screws you must pre-drill and countersink to prevent the plastic from "puckering up". Voids in the lumber, particularly the 2 x 2's and 3 x 3's, caused by air pockets during the extrusion process will not allow you to angle cut the balusters, if you like that look, for the deck railing. Plasboard, as well as most other plastic lumber, is not structural therefore railings may not meet the building code for decks a certain height above ground level. I used the 3 x 3's as railing posts because my deck is low. If it were more than two feet above ground level I would use a pressure treated 4" x 4", covered with one inch Plasboard material. If these covered wood posts are at four foot centres I believe using Plasboard 2 x 4's and 2 x 2"s for rail and baluster members would be strong and safe, particularly if you install a 1" x 6" Plasboard cap on the railing. However, check with your building code department if you have any doubts whether you are meeting the standards with this product.

To secure the deck boards I used an air nailer with three inch, epoxy coated, galvanized nails. Others I've spoken too regarding deck board installation say that they drove galvanized three inch nails with a hammer without any problems. Screwing the deck boards down is also an alternative however, it would take you a while to complete this method as each hole must be pre-drilled. The only comment I have is that I discovered it took a pretty good strike with a hammer and punch to set the nails below the deck board surface. I used a standard three inch nail as the tool to space my deck boards. Unlike traditional wooden decks, the gap between deck boards will not change as plastic lumber does not suffer from moisture loss and shrinkage.

How does this product compare with traditional wood like cedar or pressure treated lumber? The cost, including railing and stairs, was approximately $7.20 per square foot. Higher than pressure treated lumber but certainly comparable with cedar. Subtract the cost of finishing and you've got a competitive building product option. However, just as I was completing my deck I was told that a 15% to 20% increase in the cost of Plasboard could be expected. This means that the cost would rise to about $8.00 per square foot. I kept very close watch on the costs while building my deck. The total cost of $1900.00 included approximately $1000.00 for the plastic wood and the balance was for post hole digger rental, concrete, hardware, and pressure treated lumber. Its not quite a one to one ratio but it gives a rough idea of your costs when calculating the price of your new deck. Remember, the costs given are for materials only, labour costs will have to be added if you plan to have someone build your deck.

There are a few disadvantages that must be accounted for when deciding if this material is right for your deck. Product length is a maximum ten feet, air pockets and voids may force you to alter your design, colour consistency from board to board varies somewhat, and streaking caused by poor mixing of some types of plastic must be considered. However, when you weigh the dis- advantages against the fact that you end up with a maintenance free deck that never needs painting and will not rot, I believe Plasboard is an excellent alternative. I am pleased with the end result and would recommend this material. The only thing I have to deal with now is a little mountain of plastic sawdust. I guess that plastic is headed back to the land fill site.

Danny Proulx
Rideau Cabinets
P.O. Box 331
Russell, Ontario. Canada K4R 1E1
home page:
Phone: 1-613-445-3722
Fax: 1-613-445-1085

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