Silicone Sealant for Precast Concrete Panel Joints

Acetoxy sealants release acetic acid while curing. Concrete and mortar are alkaline, so the acid reacts with the calcium compounds in the substrate and leaves etching and staining around the joint that cannot be cleaned off.

Combine thermal movement with the irreversible moisture expansion that concrete continues to show over its service life. Sizing on thermal movement alone is the usual reason a precast joint tears within a few years.

Our concrete-compatible products are primerless, but the surface still has to be prepared. Concrete dust and the weak cement laitance layer must be removed — otherwise the sealant bonds to the laitance instead of the panel.

Check the substrate moisture content before sealing. Trapped moisture has to escape somewhere, and in a sealed joint it usually means the sealant blisters or loses adhesion.

Neutral cure products release no acid and contain no migrating plasticizer, so there is no staining on concrete, mortar or adjacent masonry. We can run a stain test on your own sample before you commit.

Size it from movement, not from the precast panel size alone: combine thermal movement with the irreversible moisture expansion concrete keeps showing over its service life. Then pick the movement class — our building joint sealants come as Class 25 and Class 50. Neutral cure is required on concrete and adjacent masonry to avoid acid staining. Send us panel length and site temperature range and we will work it out with you.

A silicone sealant joint on precast concrete must absorb thermal movement plus long-term moisture expansion, and the substrate is alkaline so it must be neutral cure. Width comes from the calculated movement divided by the movement capability of the grade you choose. Our primerless concrete-compatible products still need the cement laitance layer removed. Tell us the panel length and swing and we will give you the minimum width.

A neutral cure construction joint sealant. It releases no acid, so it will not stain concrete, mortar or adjacent masonry, and it contains no migrating plasticizer. Our concrete-compatible grades are primerless once the surface is properly prepared. We can run a stain and adhesion test on your own panel and brick samples before you commit.

Yes, in a neutral cure grade. Masonry is alkaline, so an acetoxy product releases acetic acid that reacts with the calcium compounds in the substrate and leaves permanent staining. Our neutral cure products contain no acid and no migrating plasticizer, which is why they are used on concrete, mortar and brickwork. We can stain-test your actual brick before you order.

For precast, add thermal movement to the irreversible moisture expansion the concrete keeps showing over its service life — sizing on thermal alone is the usual reason a joint tears within a few years. Then divide by the movement capability of the grade: Class 25 or Class 50. Also check substrate moisture before sealing, because trapped moisture will blister the bead or break adhesion.

A neutral cure, primerless concrete-compatible grade. Concrete dust and the weak cement laitance layer must be removed first, or the sealant bonds to the laitance instead of the panel. Our Class 25 and Class 50 options cover the movement range on precast panels. Tell us the joint width, panel length and site temperature range and we will confirm the grade.