Paver Patios on Mercer Island, WA

Often, but not with a conventional excavated base. The roots keeping a mature tree alive are mostly in the top twelve to eighteen inches of soil and extend well beyond the canopy, so a standard six-to-eight-inch excavation across that area severs a substantial share of them. The alternatives are relocating the surface outside the critical root area, using a shallower build-up for a lightly used seating space, or a suspended or permeable system that spans the root zone. Each has trade-offs and we will explain which applies to your specific tree rather than digging and hoping.

A textured one, and it makes a real difference to how usable the patio is in winter. Ground under a closed island canopy dries slowly, needle and leaf litter mats down and holds moisture, and a smooth sawn stone or a fine-finish concrete in that setting becomes genuinely slippery from November. A textured paver or a riven natural stone gives you grip when wet. The other practical measure is an annual clear rather than a seasonal one — needle litter left on a surface through the winter is what feeds the algae, not the rain itself.

Usually, but it changes how the patio is built and it is worth knowing that before the design is fixed. The damage from paving near an established tree is rarely the roots that get cut during excavation — it is the roots that survive and then sit under a compacted, sealed surface with no water and no air. So on the wooded Mercer Island lots the adjustments are these: keep the excavation shallow within the root zone and make up the depth with a thinner, stronger base rather than a deeper one; hand-dig around anything structural instead of running a machine through it; use an open-jointed or permeable build-up so rain still reaches the soil under the paving; and route the patio around the trunk with a generous margin rather than butting a cut edge against the bark. What we will not do is pave right up to a significant trunk and tell you it will be fine. Where the canopy is the whole reason you bought the house, the honest answer is sometimes a smaller terrace placed clear of it.

Yes. The edges of the island carry looser material than the level crown and respond more to both loading and water, so a terrace there is a structural proposition rather than a surfacing one. Adding a level platform means retaining, and retaining means drainage behind it with a properly designed outfall — not simply daylighting onto the slope, which concentrates water exactly where it does most harm. On the flat ground through Island Crest none of this applies and the work is straightforward, which is why we establish where on the island you are before anything else.