The Deck Handbook: Part 11
The (Almost) Maintenance Free Deck
One advantage of being in the general home remodeling business, rather than specializing in deck building, is that we take a broader view of how things should and could be built. Deck builders by training and experience look at deck-type solutions to deck problems. If the wood they use needs a lot of maintenance, they look for better wood and better finishes or wood substitutes such as composite or plastic decking. These are the materials they are trained on and have experience with.
We look at all these, of course, but we don't stop there. There are many possibilities outside of the traditional deck builder's craft, including materials that even the most seasoned deck builder is probably not familiar with.
If you have read the all of the prior parts of this Handbook, you know that all decks need regular and routine maintenance. No one has come up with a truly maintenance-free deck material. Wood, even expensive, exotic woods, tends to fade and discolor over time. Wood decks need regular sealing to keep their crisp look. Otherwise, they soon deteriorate into an ugly gray mess that can detract from rather than adding to the visual appeal and value of your home.
Composite decking materials, introduced with the promise of freedom from the drudgery of routine maintenance, have proven to be not nearly as maintenance free as was initially advertised. Like wood, they fade over time and turn gray if not periodically stained and sealed. In addition, they have their own particular problems associated with the use of plastics in their composition, including outright material failure. Pure plastic materials, such as vinyl decking, are nearly as maintenance free as we can get right now, but they are expensive, soft, scratch easily, and are difficult to keep looking good over time.
Aluminum offers sturdiness and freedom from most maintenance, but only at a great initial expense, and only if you love that quintessential industrial look. For most homes, an aluminum deck is prohibitively expensive. And, they can get so hot that they are not usable at all in the high summer months without a roof or pergola to shade the deck.
So, what is the solution? Can we build, using materials and methods available right now, today, a beautiful, sturdy, long-lasting very low maintenance deck that doesn't look like a commercial loading dock? The short answer is "yes". But, let's define that answer further. What we want to do is:
- Eliminate as much of the material on a deck that requires regular maintenance as we can, and
- For those materials that still need maintenance, increase the maintenance interval as much as possible. If the restaining interval is now 1-3 years, we would like to increase it to 5-6 years or longer.
Not easy, but it can be done. To do it, however, you have to let go of many of your preconceptions about how decks should be built and look a little bit outside the box.
Where and Why Decks Fail
Wood rots. It gets eaten by insects, mold, mildew, and bacteria. Some wood is naturally resistant to insect and microbe damage — the cedars and cypress, for example — because they contain chemicals that repel or kill bugs. Wood that is not naturally resistant can be made so by treatment with various chemicals that the bugs don't like. Pine is, for example, treated with copper compounds — harmless to us, repulsive to insects and many micro-organisms.
But, even very resistant and carefully treated woods need protection from water and ultraviolet if they are to be used outdoors. Pressure treatment, in most products, stops just a few millimeters below the wood surface. Water can seep into the unprotected wood and provide a splendid environment for the mold, mildew, and bacteria that consider wood to be tastier then Baskin-Robbins double fudge. Unprotected wood also fades and turns gray. This is primarily caused by ultraviolet (UV) radiation from the sun. (For more reading on how ultraviolet affects wood, see Part 6: Staining, Sealing and Maintaining Your Deck.)
The traditional protections are paint and sealants — what the building industry calls "coatings". Coatings create a barrier between the wood and the things that attack wood. As long as the barrier is intact, the wood will do well outside. Unfortunately, coatings do not last forever. Even the best UV coating has a lifespan of just a few years. Once the coating has degraded, water and sun can make short work of the unprotected wood.
However, damage to deck wood from water and sun is not uniform. The parts of the deck most exposed are the actual decking (floor) of the deck and the tops of the railings — the horizontal surfaces of the deck. The vertical members of the railings are much less affected, and the understructure, almost completely shielded from the sun, will remain undamaged long after the more exposed decking has completely deteriorated.
So, the parts we need to protect most are the horizontal surfaces most exposed to the sun, snow, ice, and rain — the decking boards themselves and handrails. Unfortunately, these are also the parts most exposed to wear and tear from normal deck use, and the parts most difficult to keep well sealed.
Non-Traditional Decking Materials
What we need are better, more resistant, materials for the deck floor — something not affected by water, sun, insects or microbes. We know that composite materials are not the answer. They are sometimes less affected, so it often (but not always, see The Deck Handbook Part 4: Composite and Plastic Decks) takes longer for them to deteriorate to uselessness, but deteriorate they will. Nor are the metals, at least not in the parts of the country where it gets hot enough to want a deck, because they get hot enough to cook on in direct sunlight.
What materials are unaffected by water or sun, do not get particularly hot in summer, are unappetizing to bugs and microbes, and do not provide a happy home for most mildew and mold?
We can think of three materials right away: brick, stone, and ceramic tile. These materials meet all of our criteria for low maintenance, resistance to deterioration, strength, and longevity.
Ceramic tile is a particularly good choice. It is very durable. There are a great many places in the world where tile dating back over 2,000 years is still in use; although, by today's standards, it is not particularly good tile. And, even if you paid almost no attention in Sister Mary Agena's 9th-grade geology class, you probably know that stone lasts a good long time.
But, lest you think we cleverly came up with this idea ourselves, you should know that in other countries tile is the standard for decking, particularly in Central and South America and along the Mediterranean. Our chief tiler, who hails from Oaxaca, thought tile was such an obvious choice that he did not understand why we were excited about it, and walked away mumbling something like "Gringos locos", which we think may be the tile of a Mexican song.
Tile on patios is common in the U.S., especially in the Southwest and on the West Coast, but the idea has not, for some reason, migrated to decks. Possibly because in the past building a strong deck understructure suitable for tile was not a trivial undertaking. It involved pouring wet concrete over a very strong superstructure, and much skill at getting it very level. Today, however, new underlayment materials have eliminated the concrete and make the process much easier and much less expensive. In fact, depending on one's choice of tile, a tile deck will cost barely more than a treated pine deck, and quite a bit less than a composite deck. But rather than lasting for a few years, will last your lifetime, and probably that of your children and grandchildren, and their children, and the children after that.
There is also historical precedent. Tile was heavily promoted by tile companies in the early 1900's as the ideal porch flooring material. It never received wide acceptance because, compared to the clear fir, spruce, pine and cypress flooring available at the time for next to nothing, tile was relatively expensive. Still, it was used sometimes, and we still find porches in the Lincoln area tiled before 1920 that are still in use. In many cases the same tile was carried into the entry foyer, providing a smooth transition from outside to inside.
Setting tile on a deck is actually straightforward. We say this because many of the technical articles we have read on the subject make it out to be some kind of arcane, mysterious, and difficult process. But, in fact, if you can set tile in a kitchen or bathroom, you can set it on a deck. Nevertheless, keep a few basic rules in mind:
- The understructure must be very rigid and stable — which is true of any tile-laying job. this means deck joists on at least 16" centers.
- The tile must be rated for outdoor use in any locality where it actually freezes in winter. (For more information on how tile is graded and which grades are suitable for outdoor use on decks, see Porcelain or Ceramic: What Is the Difference?).
- A flexible liner must be installed under the tile. This is to prevent any shifting in the understructure due to changes in temperature and humidity from telegraphing to the tile, possibly cracking the tile or its grout. The technical term for the liner is a "decoupling" membrane.
- The deck should slope slightly so water will run off easily — but not too much that walking on it, especially in snow and ice, is more excitement than you want at your stage in life.
- Only very slip-resistant tile is suitable for decks or any place else, like bathrooms, where it can get wet.
Ceramic tile is a tough, durable, impenetrable, very low maintenance material. You need to keep it swept and hose it down every once in a while. In very shaded, damp areas, you may even have to hit it with the fungicide twice a year or so to knock back mildew — but that's pretty rare. Thatís it for maintenance. Even today's epoxy or urethane grouts used on decks are very stain resistant and require virtually no maintenance.
Brick & Stone
Brick can be a little more complicated to install. Full-size bricks are heavy, so generally a sturdier deck structure is required, as are larger footings. But, there is a solution to the weight problem in the form of paver bricks. Pavers come in a variety of thicknesses, including thin pavers as little as 1" thick. These are perfect for decking.
Stone is commonly in the form of tiles, and are set just like ceramic tiles. However, irregular or "patio" stones are also suitable and can be used for very interesting effects. It is usually no heavier than tile (although very thick patio stones should probably be avoided) so no structural heavy-up is required in most cases.
Brick and stone are nearly as maintenance free as ceramic tile. Unlike ceramic tile, they are not coated with a virtually unstainable ceramic glaze, so they can stain and will fade slightly. But, then stone and tile are expected to weather and discolor over time. It's part of the charm of brick and stone.
Tile Designed Just For Decks
Ordinary floor tile is not structural. It requires stable support from a solid 3/4" sub-floor attached to a sturdy frame. But recently a company called DekTek Tile in Moose Lake, MN has started selling concrete tiles designed just for decks that do not need a subfloor. They are set between doubled-up joists and glued to the joists with a urethane-based adhesive. The spaces between the tiles are not grouted but left open so that water easily drains through the deck. A gently sloped deck to allow water to drain off the deck is not needed.
The tile is strong enough to drive a small truck over, so there is no risk of falling through a DekTek tile deck. The product's disadvantages are its cost: about $15.00 per square foot, plus shipping and installation, and the fact that since it is concrete, it needs to be sealed and re-sealed periodically. Not an onerous task, but one that is avoided if glazed floor tile is used on the deck. And, while the cost of a sub-floor is eliminated, any cost savings are offset by the substantially equal cost of double-framing the deck.
We judge it more cost-effective for new decks than retrofits, but we think this is a great idea and one that is long overdue.
Because they are vertical, wood railings are less likely to be damaged by the sun and water. Water runs off quickly, and the sun can only strike the wood at an angle. Still, since it is wood, it will deteriorate over time. So, again, the trick to lower maintenance is to get rid of as much wood as possible. With less wood comes fewer problems.
The handrails are the most exposed horizontal surface on a deck railing and are usually the first part (and often the only part) of the railing to fail. One solution for handrails is to make them out of some more durable material, like aluminum or stainless steel, largely unaffected by sun and water. The problem with this approach is that it's expensive, and results in an industrial look that most homeowners don't want for their decks.
We are still experimenting with alternative materials. One that holds promise is cellular PVC. It is essentially resistant to everything except fire. It has some drawbacks, though. It looks like plastic, which is another look most homeowners don't want. It scratches easily, and it is an ecological disaster, characterized by at least one environmental group as the most dangerous consumer product ever made. It is extremely dangerous to manufacture, out-gasses dangerous chemicals nearly forever, including dioxin, a known carcinogen, and in the event of a fire, produces very toxic fumes.
Also holding promise is fiberglass. An increasing number of fiberglass-based railing materials are coming on the market. The basic problem with these is that while the manufacturers have greatly reduced the fading problem, they have not eliminated it entirely. And, once a fiberglass railing has faded, there is no way with current technology to restore it.
So, for the moment at least, we are stuck with wood. But, to make handrails minimum maintenance we slope them so water cannot sit on them for extended periods. Standing water is what ruins handrails. We wish we had as good an answer to UV deterioration, but we don't. You just have to bite the bullet and get out the stain bucket every 3-5 years and stain and seal the railings. Sorry 'bout that! In fact, give it an additional coat every time you do it for that little extra oomph. The horizontal bottom rail on the railing, called the "shoe" is treated the same way.
Vertical wood newel posts (see The Deck Handbook: Part 1 for the names of railing parts) also must remain wood, at least for the time being. These pose a special problem because the top of the post is end-grain and end-grain absorbs water like a sponge. It must be covered, usually with a wood, plastic or metal post cap. This acts as a little roof over the post that sheds water a blocks sunlight so the post is protected. We also have to keep the bottom of the post from absorbing or "wicking" water. This is done by holding it off the ground with special galvanized anchor assemblies. A post-end should never touch concrete or soil — both are a sure path to rapid deterioration.
The more numerous wood balusters can be eliminated and replaced with a low maintenance material. The usual choices are aluminum balusters, cable railing, tempered glass and welded wire mesh. All of these give trouble free, low maintenance service for many years.
Aluminum balusters started out as simple 3/4" or 1" aluminum tubes designed to be inserted into holes drilled into the top and bottom railing of the handrail. Today, there are a variety of styles: square, bowed, and expanded with various degrees of decoration. Of course, the more elaborate the baluster, the more it costs. So, by far the most used aluminum baluster is the simple tube, and black is the most often used color. All these balusters require in the way of maintenance is a quick swipe with a damp cloth every once in a while. Virtually every manufacturer guarantees the powder coating finish for 10 years. However, over time they do tend to fade just a little on the sun side, so rotate them 1/4 turn during each annual cleaning to keep the fading even.
Cable railing requires even less maintenance. Not even a wipe down. The cables and all components of the railing system are stainless steel. There are many manufacturers marketing proprietary systems — most of which are relatively expensive. But a roll of 1/8" galvanized or stainless stranded wire from the local farm store, some turnbuckles, cable anchors and screw eyes puts you into the cable railing business without much investment in materials. The cost of cable railing is in the installation labor and heavied-up posts required. Because the railing adds a lot of tension to posts, they have to be installed in a way that will withstand the extra stress, and usually more posts are required. The railing itself is time-consuming to install and adjust. But, once the cables are installed and properly tensioned, they need adjustment only if the tension slackens — such as when junior decides to use them as a ladder. Cable railing is not as suitable as aluminum balusters for households with young children, and in many places, horizontal cable railing is illegal because of its "ladder effect". So, check with your local building officials.
Glass balusters are less suitable for use around young children. Although tempered glass is relatively sturdy, it has sensitive edges and it does not take much of a blow to an edge to break the glass.
Starting out as simple rectangular glass panels, glass balusters have evolved into more complicated shapes designed to complement just about every decor. An alternative to balusters are tempered glass panels. These are typically set in slots in the top and bottom rails, and secured with silicon. They may also be drilled for attachment using a normal stainless steel glass mount of the type used for frameless shower doors. With fewer edges exposed, and with larger, and usually thicker, glass panels, these are more suitable for rough use than the more delicate balusters.
Glass is low maintenance but not as low as aluminum balusters or cable railing. Treat the railing like a window. Every time you wash windows, also wash your glass balusters.
Welded Wire Panels
Stockmen use galvanized heavy-duty welded wire mesh to confine livestock. The mesh is strong, rust resistant and available in various sizes and shapes. Welded wire mesh is excellent for deck railings. By strong, we mean strong — it will stop a full-size hog weighing over 500 lbs. It provides the same visibility as cable railing at a fraction of the cost. It is also much easier to install than cable railing, so, installation labor is less expensive.
The most common material is mild steel treated with the same hot dip galvanizing process as chain link fencing, so it will not rust under normal conditions for very many years. The meshes are also available in stainless steel from specialty suppliers for those who live on the coasts or who just want to eliminate any possibility of rust. Meshes as large as 5" are legal in most jurisdictions for a deck railing, but we recommend smaller mesh openings where keeping junior from climbing the railing is advised. A foothold in a 4" mesh is hard to get, even for tiny toes
Like cable railing, stock meshes are virtually maintenance free, although a rust inhibitor sprayed on the galvanized meshes after about 10 years if often a good idea. Stainless panels need no maintenance at all.
The Finishing Touch
The traditional finish for a deck is an exterior stain/sealant combination. The sealant penetrates the wood, protecting it from the elements and giving it a tenacious grip on the wood so it cannot flake or peal. The stain, which usually contains UV blockers, enhances the grain of the wood and give it a nice "woody" color while preventing it from turning gray over time.
But the stain/sealant combo is not the most durable finish. The longest lasting finish is a marine-grade varnish, which is what we use on our best decks. Why a marine varnish? Well, it's designed to thrive in one of the harshest environments on earth, the oceans. Oceans don't just have a lot of water, they have a lot of salt water. Nothing could be better designed to deal a death blow to a wood finish than constant salt water.
First, we stain with a good, oil-based, penetrating stain. Then, after a suitable drying period, we apply a marine varnish made with phenolic resin and maximum UV protection. Phenolic resins are best-suited for outdoor use, and while more expensive, are the best choice for an (almost) maintenance free deck. Exposed surfaces, such as the top of handrails, get five to seven coats. Sounds like a lot of work, but since we are actually not varnishing much area, it actually takes very little time. Everything else gets two to three coats.
One benefit of using this finish is that the wood does not have to be treated with a preservative. Ordinary construction pine, fir or spruce will do just fine. As will cedar or any of the exotic woods (See: Part 3: Exotic and Imported Deck Woods.)
How long does it last? We don't know. After 15 years of using it, we have seen no deterioration in the decks we have used it on. So, the answer is: At least 15 years. But, while we suspect it will last up to 30 years, we just don't know at the moment. Check back in 10-15 years or so. We'll know more.
The Cost of an (Almost) Maintenance Free Deck
OK, how did we do?
We eliminated about 95% of the exposed wood on a wood deck, decreasing maintenance by at least that much. The only wood left is in the sheltered understructure that is not directly exposed to sun, and some bits and pieces that must, except at exorbitant cost and effort, remain wood.
Maintenance is drastically reduced. The substitute low-maintenance materials have all but eliminated periodic re-staining and sealing. You may need to touch up the top of the wood handrail every once in a while because it is the one remaining wood part of the deck that will still get blasted by the sun and rain. Even then, on a 12' x 15' deck, it will typically take you about the same amount of time as washing and waxing your car. Good news, huh?
So, how much more do all these alternative materials cost? Actually very little. You can expect to pay between 15% and 25% more initially for your (almost) no maintenance deck than you would for an all-pine deck, but less than you would pay for a cedar deck and a lot less than the cost of an exotic wood, composite or vinyl deck. So, even with all the upgrades, the deck is still a cost-effective project and a good value.
Of course, with less maintenance required, the lifetime cost of an (Almost) Maintenance Free Deck is much, much lower. The maintenance burden is virtually eliminated, saving about $9,000 over the lifetime of the deck, and a lot of backaches.