How much movement must the joint accommodate?
Estimate movement from the assembly and joint design, then confirm that the selected product and geometry cover it.
Façades and perimeters
Exterior weatherproofing
Select sealant for suitable exterior perimeters, windows, doors, façades and construction details exposed to weather.
Selection context
What this pathway helps you decide.
Start with movement and materials
An exterior joint has to remain bonded while materials move and the environment changes. Identify both bonding faces, expected movement, joint dimensions, exposure and finish before choosing a chemistry.
Two silicone starting points
Pereseal N is the neutral-cure weatherproofing option and is the first product to review for suitable construction perimeters and sensitive surfaces. Pereseal 802 is an acetoxy silicone documented for suitable glass, metal and non-porous glazing details. Their archived TDS files contain different limitations; the products are not automatic substitutes for one another.
Detail design still controls
A capable sealant cannot rescue a dirty substrate, three-sided adhesion, inadequate depth, trapped water or movement beyond the joint design. Confirm preparation, backing, primers and cure conditions for the actual project.
Before you choose
Questions that change the answer
Are either of the surfaces porous, coated or sensitive?
Cure chemistry and primer needs can change the choice. Run a compatibility test where the current TDS calls for one.
Will the joint see direct sun, rain or standing water?
Weather exposure is not one condition. Confirm UV, water, temperature and immersion limitations separately.
Is this a weather seal or structural glazing?
These are not interchangeable specifications. Pereseal pages must not be used to infer structural-glazing suitability.
Product starting points
Products to review for this application
This shortlist is not a substitute for project-specific confirmation and the current technical data sheet.
Understand the detail
Practical guidance for this work
Neutral-cure vs acetoxy silicone: what changes?
Compare neutral-cure and acetoxy silicone by cure by-product, substrates, odour, corrosion risk, weather exposure and product limitations.
Read the article
Why sealant joints fail—and what the failure is telling you
Diagnose edge adhesion loss, tears through the bead, substrate breakaway, bubbling, staining and recurring wet-area failure before choosing a repair.
Read the article
When should you use backer rod with sealant?
Learn what backer rod does, when a movement joint needs backing, how rod type and size matter, and when bond-breaker tape is more appropriate.
Read the article
How to test sealant adhesion and compatibility
Plan substrate identification, small adhesion checks, compatibility screening and formal project testing without overextending the result.
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Silicone vs polyurethane vs hybrid sealant
Compare silicone, polyurethane and hybrid sealants by movement, UV and water exposure, paintability, bonding role, substrates and maintenance.
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Acrylic vs silicone sealant: which should you use?
Compare paintability, movement, moisture, substrates and maintenance before choosing acrylic or silicone for a building joint.
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Sealant joint design basics: movement, depth and backing
Understand how substrate movement, joint width and depth, two-sided adhesion, backing, installation temperature and access shape a durable seal.
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How to inspect and maintain exterior sealant joints
Learn how to inspect exterior joints safely, recognise failure patterns and decide between local repair and full replacement.
Read the articleConfirm the application
Share the substrates, dimensions and exposure.
We will help narrow the range and locate the relevant technical documents.