Insulation that performs well indoors can deteriorate quickly when exposed to outdoor conditions without adequate weather protection.
On roofs, plant decks and other external installations, pipework and ductwork are often insulated using the same materials found inside buildings. The challenge is exposure to the elements. Rain can penetrate unprotected insulation, UV radiation can degrade facing materials over time, and moisture ingress can significantly reduce thermal performance. In severe cases, insulation may need to be removed and replaced.
To prevent this, external insulation systems are typically protected with weatherproof finishes such as Proclad and PIB sheeting. These protective layers help shield insulation from moisture, UV exposure and physical damage, maintaining performance and extending the lifespan of the installation.
Why external insulation needs a weather barrier
Indoors, foil-faced lagging is usually left as it is. The foil holds its shape, keeps the insulation clean, and there is little to attack it. Outside is a different matter. Wind-driven rain, standing water and constant UV all take their toll, and insulation that is wet is insulation that is not performing properly. Sealing the lagging against the elements protects the thermal performance you have paid for and helps protect the substrate underneath from corrosion under insulation. H&V supplies two products designed for exactly this: Proclad and PIB sheeting.
Proclad, a clean cladding finish
Proclad, from Protech Global, is a self-adhesive multi-layer cladding that fits over insulation and seals with tape. It provides a neat, hard-wearing outer skin that stands up to rain and UV, and it comes in a range of finishes including grey, silver and white, so it can be matched to the look of the site. Because it is self-adhesive, it is straightforward to apply on site, and the taped joints help keep the whole run sealed. It suits projects where appearance matters as much as protection, such as visible rooftop plant or exposed runs on a finished building.
PIB sheeting, a tough rubber membrane
PIB sheeting is a polyisobutylene rubber membrane applied over lagging to seal it against the weather. It is a robust, flexible layer that wraps the insulation and stands up to rain and UV. PIB comes in black and is a dependable choice for general external weatherproofing where a hard cladding finish is not required. On complex shapes and fittings, a flexible membrane can be quicker to dress than a rigid cladding.
Choosing between them
Both products do the core job of keeping water and UV away from external insulation, so the choice usually comes down to finish and application. If you want a clean, matched outer surface, Proclad gives you a range of finishes. If you want a flexible membrane that dresses easily around awkward fittings, PIB sheeting is often the simpler option. Many sites use both, depending on what each section calls for. If you are not sure which is right for a particular run, the team at your branch can talk it through with you.
Everything from one supplier, delivered to site
H&V stocks both Proclad and PIB sheeting, alongside the lagging, tapes and fixings that go with them, all from leading manufacturers and all listed in our monthly price list. With three branches covering Romford, Peterborough and Mansfield, and free next-day delivery on the vast majority of orders, you can have the right materials on site when the weather gives you the opportunity to get the work done. That is the H&V Promise: getting your order to site when and where you need it.
To check stock or discuss the right finish for your next external job, speak to your nearest H&V branch or download the latest price list at hvinsulation.com.
Frequently asked questions
Does insulation fitted outside really need weatherproofing?
Yes. Outdoor insulation that is left unprotected can absorb water and degrade under UV exposure, reducing its thermal performance and potentially leading to corrosion under insulation. A weather barrier such as Proclad or PIB sheeting helps keep it protected.
What is the main difference between Proclad and PIB sheeting?
Proclad is a self-adhesive cladding that provides a clean, finished surface in grey, silver or white. PIB sheeting is a flexible rubber membrane in black that dresses easily around fittings. Both help protect external insulation against rain and UV.
Photo courtesy of OJM Insulations Ltd