A well-designed patio must take into account the terrain, landscape and the needs and pocketbook of your family.  Not all yards are candidates for a patio.  In uneven terrain, a raised deck - which can span hill and dale - might be the best option for outdoor space.

We needed to tie in our patio with existing trees, planting beds and decks.  We measured everything and made a small scale drawing of our home and existing landscape on paper (Fig. A).  We used a straight, 16' 2x4 with a 4' level on it and a tape measure to get a rough idea of how much our yard sloped (we noted that on our drawing).  Then we laid tracing paper on top of our scale drawing and doodled a half-dozen patio designs.  A consultation with a landscape designer provided us with these helpful tips:

• Patios must have a slight slope (1" for every 4' to 8') for proper drainage.  If you don't provide enough slope, rainwater will settle into low spots, eventually softening and washing out the sand and sub base materials beneath.   A flat or poorly sloped patio could even direct water into your basement.  Too much slope and you'll feel you're on a listing ship. Bear in mind you can build up low spots with an extra-thick layer of sub base.
• Ask yourself how you'll be using your patio.  Our expert recommended a minimum of 25 square feet of patio per house occupant.  He also added that a patio at least 16' long in one direction is often the most functional.  Plan for at least a 6 x 6-foot area out of any traffic path for a dining table and chairs.  Do you need space for a grill?  A wading pool?  Planters?  Hopscotch?  Sketch these on your tracing paper as you doodle.
• In small areas, use simple pavers and patterns (like the running bond shown in Fig. B).  In large areas, you can break up the expanse with a variety of patterns or dividing bands.

• Curves add interest and grace to the patio - but also loads of cutting and extra work. 
   

PAVERS: BEAUTIFUL, VERSATILE, MANAGEABLE

One of the beauties of pavers is that together they create a large, durable space, but individually they're lightweight and easy to install.  This gives the permanence of concrete without the special tools, know-how and "hurry-up ness" that the concrete requires.  Plus, pavers have color, shape, and pizzazz.

There's no doubt about the durability of concrete pavers.  They're often used in streets and industrial parking lots where heavy machinery cracks ordinary concrete slabs.  Pavers - small and independent - withstand abuse by flexing, rather than cracking, under pressure.  They're ideal for regions that go through freeze/thaw cycles, too; the individual pavers absorb heaving and movement without cracking.  And it's a lot easier to repair small areas in a dry-laid patio than with a slab.

The first thing you should think about is where the last paver you lay will end up.  Will your yard accommodate the slope and size of your patio?  Will a square patio end in nice, full pavers, or skinny little slivers?

With your graph paper plan in hand lay down a garden hose (1) and 2x4s to form an outline of your patio.  Use your level and a straight 2x4 to double-check the lay of the land for a proper slope.  Then spray-paint a line 8 inches outside the outline of your patio to act as a line for excavating.   Strip away the sod at this point (2), so grass doesn't get in the way of the guide strings you'll soon be setting up.

 

EXCAVATING THE SITE AND BUILDING THE BASE

This part of the project is the key to a successful (and long-lasting) patio.

Use the bottom of a door or a set of stairs abutting the patio area as the starting point for establishing the final height and slope of your patio.  Your entire slab should slope away from the house at a rate of 1 inch every 4 to 8 feet. This slope may be one long decline or a slight dome-shape so water runs off in more than one direction.  Place one end of a long 2x4 at the bottom of the stairway or an inch below the door threshold, then level across to stakes driven at the perimeter of the patio and make a mark (3).  Make another mark the appropriate distance down the stake to indicate the slope.  In our case, after making a level mark on our stake with a level and 12-foot 2x4, we made another mark 2 inches down to indicate a slope of 2 inches for that 12 feet. (1 inch for every 6 feet)
 

Make a grid work of stakes and guide strings to indicate the finished height and slope of your patio, then excavate 7-1/2 inches below these lines.  This will provide room for a 4-inch sub base, the 1-inch sand base, and the 2-1/2 inch pavers themselves (4 inches + 1 inch + 2 1/2 inches = 7 1/2 inches).  See Fig C.  If the area is hilly, you will need to go back and forth between excavating, leveling and setting strings to get things right.

Soil conditions vary greatly across the country.  If after digging 7-1/2 inches below your strings, you still find pockets of loose dirt or black soil, remove it or it will eventually settle, creating a wavy patio.

Next, bring in the sub base material.  Bring the area up to a height 3-1/2 inches below your strings (4).  It should be at least 4-inches deep in all places.  The sub base should extend 8 inches beyond the actual edge of the patio to provide room for the edging.  It's possible you'll need to build up an area to accommodate your patio.  In such cases, remove the sod and loose soil, then build up the area with your sub base material.  Building a 10 to 12-inch sub base is common; even 20 inches would not be unusual. Compact the class 5 using a flat-plate vibrator (also known as a compactor) as shown in picture 5.  Go over the entire area twice.

SPREADING SAND

Sand provides the final base for your pavers.  If this surface is uneven, the pavers on top will be, too.

Ideally, the sand should be 1 inch thick, but if it's a tad thicker or thinner in spots, that's okay.  What you want is a firm, flat surface for laying pavers.  Sand also locks the pavers in place.  When you vibrate the pavers in place, they'll bed themselves slightly into the sand.

If your patio is under 10 feet wide, use a screed board with a 3/4-inch notch on the ends to ride along the Snap Edge to level the sand. On larger expanses, level long lengths of iron pipe in the sand 2 inches below your guide strings, then run your screed along the top of the pipes.  (When you're done with the pipe, remove it, then fill the groove it leaves with sand).  In many cases you'll use a combination - a notched screed board riding along the Snap Edge on one end, with the other end of the screed running along iron pipe (picture 8).  Whichever screeding method you use, roughly dump and level the sand over the compacted sub base, then fill in low spaces and rake away excess sand as you drag your 2x4.  Shuffle the screed lightly from side to side as you work. You're not compacting the sand, just creating a firm, solid bed.  Screed only as much sand as you can cover with pavers in one day.  Screeded sand left any longer is guaranteed to be ruffled by wind, rain, kids, or a stray cat thinking he's found the world's biggest litter box.

THE ESSENTIAL EDGING

Edging is an absolute must for maintaining the integrity of your patio.  Without solid edging, your sand base and pavers will separate and drift apart as rain, frost, and foot traffic pound away.

Snap Edge plastic edging, left uncut, remains straight and rigid, but when it's cut, it can be bent to form curves.  Secure the Snap Edge into the compacted sub base with 8" - 10" spikes (picture 6).

We used landscape timbers for combination edging/steps in a sloped area of the yard (picture 7).  Crisscross corners and use double timbers on the front of steps (even though the lower one will be buried).   This lower timber prevents the sub base and sand from washing out.  The tops of the timbers should be at the same height as the surface of the finished patio.

SWEEPING AND UPKEEP

Spread coarse sand across the surface of your patio.   After the sand dries, sweep it around the patio (picture 15) to fill the spaces between the pavers.  Make sure the sand is dry - wet sand will bridge, rather than fill the gaps.  It may take two sweepings with a push broom a few days apart to completely fill the gaps.  The sand helps solidify the pavers, and also fills any spaces where dirt might enter to provide a mini-planting bed for weeds.  We rolled two coats of a water sealer over our completed patio.