What is the greenest way to build a deck? Is it okay to use pressure-treated lumber? What is the best way to attach it to the house? What kind of decking is the most sustainable, and what is the best method for attaching the deck boards to the framing? Should the surfaces be finished? With what product? These are just some of the questions I hear about creating outdoor living space.
My answer is always that the greenest deck is a patio. Sure, wooden decks or balconies are usually the only options if they have to be significantly above ground level, although there are masonry- and petroleum-based products that can work in those applications.
Outdoor living space is a great way to expand our living area without increasing the amount of conditioned space: it gets us out into the open air, into the nature we’re trying to preserve with the green building movement. But asking any “green” material to stand up to the environmental exposure a deck is subjected to is asking a lot. When the outdoor living space is going to be at or near grade, a patio—the masonry equivalent to a deck—can be a greener choice.
If the word “patio” conjures images of dirty concrete with weeds growing up through cracks, there are other options. Harvesting “urbanite” for reuse by breaking up the old concrete into manageable pieces is one example; overlaying a drainage layer and topping it with permeable surface paving is another. On a recent project, we used granite stones salvaged from a crumbling foundation, which our skilled mason assembled into the intricate, recessed patio shown in the photo above.
Commercially available, cement-based, interlocking modular paving blocks can be an affordable choice, although I am partial to square concrete pavers set in a bed of crushed stone for a more formal look, or flagstones (flat, natural “cleft” surface fieldstone) for a rustic feeling. An artist I know built a very interesting patio using a mix of broken stone countertops, tiles, and glass. Slate roofing could be recycled into patio paving, but, like tile, the small, thin pieces would not be stable underfoot unless set into a bed of mortar. Stacked closely together on edge, though, the thin edges would create a unique, usable surface.
Brick, a classic patio surface, is hard to beat for its combination of warm color and texture. Bricks can be locally produced in most parts of the country or recycled from old buildings. Durability can be an issue in areas that freeze, though; look for “hard” bricks, tempered for use as paving, or be prepared for them to disintegrate over time into their original form of clay particles.
Drainage options will vary depending on several factors. If the patio sits on a well-draining site, it will be best and easiest to use a permeable base layer such as crushed stone and leave gaps in the paving material to allow stormwater to drain through. The gaps can be filled with the same material, or planted with moss (if it’s shady) or thyme (if it’s sunny). Weeds can be easily killed with a 50% solution of vinegar, or scraped out with a brush designed for the purpose. Personally, I would not use a chemical such as Round-Up or burn the weeds with a flame, but those are other options, probably no more harmful than standard deck maintenance techniques. If the site does not drain well, start with a well-compacted base of gravel with graduated particle size so that the particles lock together. On top of that, build a drainage layer using crushed stone, with a drain tile (4-in. perforated pipe works well) to direct water to another part of the site if necessary.
Keep the size to roomlike dimensions, and when in doubt, make the length 1.6 times the width for a pleasing proportion. Patios need a sense of enclosure to feel inviting; masonry walls or shrubs and plantings create a feeling of containment. When a tall wall looms over an abutting patio, bring the scale down with a trellis or pergola, or pull the patio away from the house a bit and plant a tall shrub or small tree between it and the house. Full sun can make a patio (or deck) uncomfortably hot; a patio umbrella or a trellis covered with vines provides respite.
Consider low-level lighting and a source for cooking fuel—wood or gas—in the planning stages. Outdoor cooking appliances keep heat out of the house (look for Energy Star models) and can be connected to natural gas or large propane tanks, if available on site. Or, build a fire pit or an outdoor barbecue. The kitchen has taken over the indoors as the heart of the home, the primary gathering spot; duplicating kitchen functions outdoors will ensure that the patio is well-used.