Patio paving
Flat where you sit, sloped where it counts
A patio does not carry cars, so the base does not need to be as deep as a driveway. Four to six inches of compacted aggregate base is the ICPI figure for a surface that only takes foot traffic and furniture. What a patio does have to do is stay perfectly even, because a rocking table leg or a lip you catch your toe on is noticed every single day.
The catch is that it also has to drain. A patio sits against the back of your house, which is the last place you want water standing in February. So we build in a fall of about a quarter inch per foot running away from the wall. That is enough to move water and gentle enough that nobody standing on it can feel the slope.
We only work in interlocking pavers and natural stone, built to ICPI specification and backed by a 20 year warranty. Plenty of the patios we build over in Burlingame are sitting where an old brick terrace used to be.
How is a patio base different from a driveway base?
Mostly in depth. A patio gets four to six inches of compacted aggregate base, a driveway gets eight to twelve, because the load from a car has to be spread out before it reaches the soil and the load from a chair does not. Everything else about the build is the same: excavate, compact the subgrade, fabric where the soil is soft, then base rock in layers with a compactor over each one. That sequence does not change from one end of our work to the other.
The soil is what changes the number. Flat ground near the bay, and a lot of the low lying parts of Menlo Park are exactly this, sits on clay that swells with the winter rain and shrinks back in summer. On ground like that we go deeper and we put geotextile fabric between the clay and the base stone, so the stone cannot work its way down into the soil over the years.
Which way should a patio drain, and how much fall does it need?
Away from the house, always, at roughly a quarter inch of fall for every foot of run. On a twelve foot deep patio that is three inches of drop from the wall to the outer edge. Walk on it and you will not notice. Pour a bucket of water on it and it is gone.
We set that fall in the subgrade, hold it through the base, and hold it again in the screeded sand, so by the time the pavers go down the slope is already built in. Where a patio is boxed in by a wall or the ground rises behind it, the water has nowhere to run to and we put in a channel drain or a dry well before we pave. Nobody enjoys hearing that on estimate day, but it is a lot cheaper than lifting a finished patio in year two. It is the same guidance published for the Belgard range we are certified to install.
Get a free estimate on your paver patio
Belgard Master Craftsman, ICPI certified, and a 20 year warranty on every installation.
Call (650) 705-0628What stops the patio spreading at the edges?
Edge restraint. Interlocking paving holds together because every unit is braced by the ones beside it, so the outer row has to be braced by something too. On a patio that usually means a spiked polymer edging pinned into the base, hidden under the soil or the mulch line, or a mortar set border course where we want the edge to be part of the design.
Leave it out and the perimeter pavers push outward under normal use, the joints open, joint sand washes into the garden and the whole field slowly unravels from the outside in. Once the restraint is in, we sweep polymeric sand into the joints, mist it, and run a plate compactor with a protective mat across the finished surface. That seats every paver into the sand bed and drives sand up into the joints. Exactly the same restraint and joint sand go into a front entry path when we build one at the same time.
Why choose Exterior Designs for your patio?
We are a family owned business on El Camino Real in San Carlos, and our owner is an ICPI Certified Paver Installer and a Belgard Master Craftsman. We lay Belgard, Calstone and McNear, and we only work in interlocking pavers and natural stone, so paving is not a side line for us.
Every patio is built to ICPI specification and carries a 20 year warranty. We are rated 5.0 on Google and estimates are free. Call (650) 705-0628 or line up a free estimate and we will walk the yard with you, look at where the water goes, and give you one honest number.
Ask a paver installer
Straight answers about paver installation on the Peninsula
How long does a paver patio take?
Most back garden patios are a three to four day job. Excavation and haul out first, then the base compacted in layers, then the screeded sand and the pavers, then cutting, edge restraint and joint sand.
How far should the patio sit below the door threshold?
Low enough that rain never has a path back toward the house. We set the finished paving below the door sill, slope it away from the wall, and keep it clear of any wall vents or weep holes.
Will furniture legs mark or sink into the pavers?
No. Pavers are dense units on a compacted base, so chair legs and table feet do not press in the way they do on a lawn or on gravel. Dragging metal furniture can scuff them, so fit felt pads.
Can you build a patio around a tree?
Yes, carefully. We keep the paving off the trunk, hand dig near the big roots instead of cutting them, and leave an open ring so the tree still gets water and air. Any area a root lifts can be reset later.
What is the difference between pavers and natural stone?
Pavers are made to a consistent thickness, so they lay fast, sit flat and come in matched colors. Natural stone varies in thickness and has more character, and each piece is bedded by hand. We install both.
Do you build patios outside San Carlos?
Yes. Belmont, Redwood City, San Mateo, Burlingame, Hillsborough, Menlo Park and Atherton are all in our regular area, and our crew has built patios in Foster City, Los Altos, Pacifica and Fremont as well.