SEK Perm Chips Joint Aggregate: Permeable Paver Joint Guide

SEK Surebond Perm Chips is the chip a permeable joint is actually supposed to get. Permeable interlocking concrete pavement, PICP for short, only works if the joint aggregate is clean, angular and correctly graded. Rounded or dirty stone packs down, clogs and stops the water. SEK describes Perm Chips as crushed and washed granite with a 100 percent fractured surface that meets ASTM #9 stone specs, which is the spec PICP designs are written to.

This guide covers what Perm Chips is, why the aggregate spec matters so much in a permeable pavement, where SEK says it is used, the three colors, how the chip is kept in the joint, and how to size an order, using figures from the SEK Surebond Perm Chips product page. Where the product page does not state a figure, we say so and point you to the manufacturer documents in our TDS and SDS library.

What Perm Chips is

SEK Surebond Perm Chips Permeable Paver Joint Aggregate is a loose stone, not a binding sand. In a permeable pavement the joint is the drain, and every design assumption about infiltration rate depends on the aggregate holding an open structure under traffic. Here is how Perm Chips compares with the rounded or unwashed stone that ends up in permeable joints when nobody checks the spec:

Feature	Rounded or dirty stone	SEK Perm Chips
Particle shape	Rounded, rolls, packs and closes	100 percent fractured surface, every face angular, so it interlocks
Fines	Dirty stone carries fines that clog the joint	Crushed and washed granite; washed matters as much as crushed
Gradation	Unspecified	Meets ASTM #9 stone specs, the standard PICP joint aggregate gradation
Winter	Can break down into fines	Freeze and thaw resistant, does not break down into fines over winters
Result under traffic	System stops performing long before water is seen standing	Keeps its voids and resists clogging and particle build up

SEK's short version: angular fractured stone locks together and keeps its voids, and washed stone keeps the fines out that would otherwise fill them. If you are new to the difference between a permeable joint and a sealed polymeric joint, polymeric sand vs resin sand explains why a permeable system needs the opposite of what polymeric sand does.

Perm Chips specifications

Specification	Per the SEK product page
Product type	Permeable pavement joint aggregate
Manufacturer	SEK Surebond
Material	High strength crushed and washed granite
Standard	Meets ASTM #9 stone specs
Surface	100 percent fractured
Package	50 lb bag, 56 bags per pallet
Colors	Saturn Tan, Stormy Gray, Eclipse Black
Durability	Freeze and thaw resistant
Joint width	Standard or narrow joints

The colors as SEK describes them: Saturn Tan is a warm light aggregate, Stormy Gray is a neutral grey granite, and Eclipse Black gives a dark contrast joint. The Perm Chips color samples let you set each one against your paver before you order. The product page does not publish the full sieve analysis, a coverage figure or a bedding spec, so for those check the manufacturer documents in our TDS and SDS library.

Where to use it (and where not to)

SEK lists Perm Chips for:

• Permeable interlocking concrete pavement, PICP
• Standard and narrow permeable joints
• Commercial, municipal and residential permeable installations
• Anywhere an open graded joint aggregate is specified

The joint width rating is "standard or narrow joints." SEK does not give that as a dimension on the product page, so if you are working from a PICP design, match the aggregate to the joint width and design infiltration rate on the drawing. SEK's own guidance is that joint width and design infiltration rate decide the aggregate; send us the detail and we will make sure the chip matches the spec. Call (856) 418-4895 or use the contact page.

Where it does not belong is any joint you want sealed. Perm Chips is meant to stay open. A patio on a conventional compacted base with no drainage layer underneath wants a polymeric sand such as SEK Surebond PolySweep, not a loose chip. And if you want a permeable joint that is locked rather than loose, SEK's PS1500 permeable jointing compound is the other option within the brand family. SRW WetLok is a premixed jointing sand that is permeable after it sets.

How to install Perm Chips

The SEK product page does not publish a numbered installation procedure for Perm Chips, and the only manufacturer document it lists is the safety data sheet. Because PICP is an engineered system, the installation sequence, bedding depth and compaction requirements come from the pavement design and the paver manufacturer's PICP guidance, not from the aggregate bag. What the SEK product page does establish:

1. Confirm the spec. Check that the design calls for ASTM #9 joint aggregate and that the joint width is standard or narrow, which is what Perm Chips is rated for.
2. Keep it clean. The whole point of washed granite is the absence of fines, so keep the chip free of mud and debris on site. Fines are what clog a joint.
3. Fill the joints with Perm Chips. The chip is loose stone; it is not activated, watered or mixed.
4. Stabilize if the job calls for it. Loose chip scatters and gets lost to traffic, wind and vacuum maintenance. SEK makes SB-1000 PermStik to stabilize the chip in place without sealing the joint closed, which is the pairing most commercial permeable jobs specify. Follow the PermStik instructions for that step.

The product page gives no temperature, moisture or cure requirements for the chip itself, so we do not state any. If you pair it with PermStik, that product's own conditions apply.

How much Perm Chips you need

The SEK product page does not state coverage per 50 lb bag for Perm Chips, and we will not estimate a figure the manufacturer has not published. Coverage for a joint aggregate depends on paver size, joint width and joint depth. Measure those three, then use our polymeric sand calculator to work out the joint volume for your layout. Check the manufacturer data sheet in our TDS and SDS library for the coverage figure, or call (856) 418-4895 with your square footage, joint width and depth and we will help you settle on a bag count.

Warranty and testing

SEK states that Perm Chips meets ASTM #9 stone specs, has a 100 percent fractured surface, and is freeze and thaw resistant. The product page does not state a warranty term or additional lab results, so we do not claim any. The safety data sheet opens from the manufacturer, so you always get the current revision, and it is listed in our TDS and SDS library.

Frequently asked questions

What does ASTM #9 mean for a permeable joint?

It is the standard PICP joint aggregate gradation, the spec permeable interlocking concrete pavement designs are written to. SEK states Perm Chips meets ASTM #9 stone specs.

Why does the stone have to be washed as well as crushed?

Because fines are what clog a joint. Crushing gives the angular faces that interlock; washing removes the fine particles that would otherwise fill the voids and stop the water.

Will Perm Chips break down over winter?

SEK lists it as freeze and thaw resistant, meaning it does not break down into fines over winters.

How do I keep the chip from scattering?

SEK makes SB-1000 PermStik to stabilize the chip in place without sealing the joint closed. SEK says that pairing is what most commercial permeable jobs specify.

Can I use Perm Chips on a regular patio instead of polymeric sand?

Not if you want a sealed joint. Perm Chips is built to stay open so water drains through it, which is the opposite of what polymeric sand does. For a conventional base, use a polymeric sand.