Bedding sand for pavers — why the type and the thickness both matter.

The right sand: ASTM C33 concrete sand

• Clean and washed (no clay, no organic material, no fines that hold water)
• Sharp and angular grains (locks under compaction instead of rolling)
• Multi-sized particles from about #4 down to #100 sieve
• Sometimes called 'concrete sand' or 'sharp sand' at the supply yard
• Gray-brown color, gritty feel, no soft fine dust

What NOT to use as bedding sand

• Mason sand — too fine, too uniform, washes out and pumps under load
• Play sand / sandbox sand — round soft grains that never lock together
• Beach sand / desert sand — round particles, no structural integrity
• Quarter minus — contains fines, holds water, can pump up into the joints
• Stone dust — variable fines content, doesn't screed clean to 1"
• Whatever's left over from another job — bedding sand has to be the right spec, period

The 1-inch rule (and why thicker is worse)

Bedding sand is set up by 'screeding' — pulling a straight bar across two screed rails to leave a smooth, even 1" layer. That's the entire purpose: 1" of consistent thickness so every paver seats to the same plane.

• 1" screeded is correct — more is not better, it's worse
• Thicker layers (2"+) migrate sideways and create low spots over time
• Sand is NOT a substitute for a proper compacted base — fix the base, don't add sand
• Once the pavers are set, the sand should NOT be re-compacted before laying — only after
• Final compaction of the laid pavers locks them into the sand for good

How bedding sand fits into the paver layer cake

From the bottom up, a correct paver install looks like:

• Compacted native subgrade (cleaned, leveled, compacted in place)
• 4–12" of compacted ABC base — installed in 2–3" lifts
• 1" screeded concrete sand (this page)
• Pavers set tight to a string line or screed plane
• Polymeric sand swept into joints, misted to activate
• Final compaction over a protective pad to lock everything together

Polymeric joint sand vs bedding sand (don't confuse them)

• Bedding sand: 1" layer UNDER the pavers (this guide)
• Polymeric joint sand: swept BETWEEN the pavers after install, then misted to harden
• Bedding sand is structural-leveling; polymeric sand is lateral lock + weed/ant block
• Both are required on a quality install — they do not replace each other
• Polymeric sand typically needs refreshing every 5–10 years; bedding sand should never need attention

How to tell if your contractor is using the right sand

• Ask them by name — 'concrete sand' or 'ASTM C33' should come right out
• Look at the sand on site: gritty, angular, multi-sized = good; soft, fine, uniform = wrong
• Watch them screed — there should be two parallel rails and a straight bar pulled to 1"
• Bedding sand thicker than 1" — ask every bidder to specify bedding depth and material in writing
• Ask what's getting swept into the joints after install — should be polymeric sand by name

When old patios start rocking

If you're calling us because your existing patio has rocking pavers or low spots, the fix isn't sweeping more sand into the joints. It's pulling the affected area, inspecting the bedding sand and base, and rebuilding correctly. Done right, the affected zone is solid for the life of the patio — and we can tell within five minutes whether the original install used the wrong sand or just skipped base compaction.