The usage of non-curing butyl polymeric sealants was first launched to the U.S. roofing trade greater than 60 years in the past and is now gaining traction within the photo voltaic trade as a sealant for roof attachments, offering robust weatherproofing capabilities and prolonged service life.
A threaded fastener pushed via the butyl tape manufacturing unit utilized to S-5!’s VersaBracket steel roof attachment. S-5!
Butyl sealants are fashionable as a result of they’re simple to use in both chilly or scorching temperatures. Non-curing butyl compounds have a sticky structure — like chewing gum — that’s retained all through their service lives, even in excessive temperatures. These sealants are sustainable, non-toxic and environmentally pleasant. They require little, if any, floor preparation — simply clear any seen dust and floor particles. The sealant “tacks” (clings) to threaded fasteners pushed via it, offering extra secondary climate safety.
Though pump-able tube grades of butyl (72%± solids) can be found, extruded tapes (98%± solids) are strongly most well-liked because of their manufactured dimensional consistency somewhat than the discretion of a person squeezing a caulking gun and guessing how a lot is sufficient. Each over- or under-application could be detrimental to efficiency.
A service life examine performed by the Metallic Development Affiliation was led by Rob Haddock, CEO and founding father of photo voltaic mounting producer S-5!, reveals that brand-specific butyls nonetheless display distinctive elasticity, adhesion, cohesive tensile energy and webbing properties after 35 years of service. Primarily based on lab research of these specimens taken from 14 aged roofs, the identical sealant chemistries are estimated to final 60-plus years.
Butyl formulations have modified, and plenty of have improved through the years, however it is very important notice that butyl polymers aren’t all created equal and there aren’t any requirements that management their composition. Isobutylene rubber is mixed with isoprene and is often under 20% of the formulation. (The next rubber ratio doesn’t imply a greater sealant compound.) Ultraviolet (UV) inhibitors, insect and fungal repellants are sometimes components, however precise formulations are all proprietary commerce secrets and techniques and differ extensively.
A lab chemist who absolutely understands sealant sorts could run some exams for cone penetration, tensile energy and adhesion, however these exams are merely formative years indicators. The one sure measure of aged efficiency of butyl polymer sealants is the documented historical past of brand-specific, long-term efficiency on actual roofs over a long time of time. Formulations that aren’t in a position to face up to the check of time can harden, lose adhesion or exhibit compound breakdown (de-polymerization) in a fraction of time when in comparison with their counterparts.
Webbing, elasticity and adhesion of butyl inside a joint after 34
years of service. Rob Haddock, Metallic Roof
Advisory Group
The butyl sealants that S-5! has been pre-applying to its steel roof attachments for 32 years, for the reason that firm’s inception, primarily based on its founder’s expertise and suggested by specialised sealant chemists and inspecting brand-specific butyl efficiency not solely within the lab, however on hundreds of roofs and over a long time.
It’s vital to make use of solely supply-side sources for butyl which have a minimal of 40 years’ empirically confirmed historical past to make sure correct efficiency. Creating the best product design to pre-apply the sealant is equally essential as sourcing a confirmed butyl compound. Making use of the correct amount with the best geometry, whereas stopping over-compression and publicity to dangerous UV are all vital design components. All of S-5!’s attachments with pre-applied butyl have a reservoir to forestall over-compression, thinning and UV publicity, all of which may compromise butyl’s service life.
Subsequent, to substantiate a correct design, additionally it is essential to leak-test attachment merchandise with pre-applied sealants of their particular utility. Probably the most demanding, but in addition essentially the most relevant for roof attachments, is ASTM E2140, The Customary Check Technique for Water Penetration, the static water check that Haddock helped to develop 40 years in the past at ASTM.
Past selecting a butyl sealant with a historical past of dependable efficiency and designing attachments correctly to pre-apply butyl tape, the next are some greatest practices when utilizing sealants to leak-proof photo voltaic photovoltaic roof attachments:
Don’t use any sealant as a surface-applied repair on a roof. Floor purposes are topic to degradation from UV, ozone, mechanical abrasion, dust and different contamination. Butyl polymers are significantly susceptible to UV publicity. If sealants aren’t correctly protected, a number of components can break down their chemical bonds. Utility of butyl in gasket trend will assist shield the sealant from these threats. However even when utilized as a gasket, one of the best sealants nonetheless have vulnerabilities. Search for attachments the place the sealant is hid from publicity and is minimally extruded at outward edges of the half when put in.
Keep away from over-compression. Tighter will not be higher on this case. Once you drive the screw, seat it, however don’t over-torque it. In any other case, you may skinny and displace the gasket materials, lowering its life and effectiveness. The perfect apply is to make the most of an element design that includes a built-in recess to encapsulate the fabric and inhibit over-compression
Manufacturing unit-applied butyl tape within the base of an S-5! SolarFoot steel roof attachment. Patrick Thompson/S-5!
Predominant takeaway
The expansion of non-curing butyl polymers to seal roof attachments within the photo voltaic trade is a optimistic development, as butyl is a sealant with long-lasting efficiency. Together with elevated use comes the elevated duty to make use of sturdy formulations from confirmed sources to match the lifetime of the photo voltaic and roof system. A greatest apply is to make use of pre-applied butyl to make sure the sealant works as designed and is rarely compromised throughout set up and for the service lifetime of the whole photo voltaic and roof system. Be taught extra about butyl sealants in S-5!’s weblog all about butyl.
