Durable glazing systems require durable seals

The choice of professionals

Bostik Benelux BV specializes in the development and ISO-certified production of high quality sealants, adhesives, PU foams and technical sprays for construction and industry. The company has grown to become one of the largest adhesive and sealant manufacturers in the world. Its products are known under the brand names Bostik, Zwaluw® and Hercuseal and under the private labels of various partners.

One of the best-known brands in the Bostik range is Zwaluw®. "Zwaluw® is the market leader in the Benelux in adhesives, sealants, PU foams and technical sprays, aimed at professional end-users in the building and construction industry," says Hans van Houwelingen, Sales Manager at Bostik. "The range includes more than two hundred professional products in the field of sealing, glazing, fastening and finishing, at a good price-quality ratio. The products can be divided into different technologies (acrylates, silicones, hybrids, PU foams, adhesives, technical sprays and related articles) and applications. For example, we offer complete solutions for construction work (gluing, filling and fitting), painting jobs (connecting joints) and glazing jobs (top seals)."

Dutch glazing guidelines 

Zwaluw® glazing products from Bostik are developed exactly according to the Dutch glazing standards and codes of practice (NEN 3576 and NPR 3577). They cover: 

- glazing of buildings

- new and existing frames

- windows and doors made of wood, plastic or metal (aluminum, steel)

- vertically arranged panes, imposed on four sides, framed all around in the rebate

- With an area not exceeding 5 m² per pane

- and a maximum thrust pressure of 1.6 kN/m².

NPR 3577 lists two sealing systems for glazing: 

- System K (sealing with elastic sealant/wet glazing);

- System P (sealing with rubber profiles/dry glazing).

For System K, the Code of Practice requires the use of elastic glazing sealants that meet the certification for glazing in accordance with CE EN 15651-2: G-CC, with a motion capture and class of 20LM, 20HM, 25LM or 25HM. Here LM stands for Low Modulus (softer sealant) and HM for High Modulus (harder sealant). On Zwaluw® glazing products this certification is mentioned both on the tube and on the technical specification sheet.

Helpful selection guide

Various elastic glazing sealants are available for sealing glazing. "The choice depends on several factors, such as the desire for paintability, glass type, joint size and skills of the processor," says Van Houwelingen. To make the choice easier, Bostik has developed a handy product selector with the most important product characteristics. "This tool shows at a glance which glazing sealant is most suitable for which application."

Durable and elastic glazing sealants

Bostik's product range includes various Zwaluw® glazing sealants. Van Houwelingen is the first to mention Zwaluw Hybriseal® 2PS (Two Paint System); a durable and highly elastic glazing sealant to which water-based and synthetic paints adhere excellently. "Zwaluw Hybriseal 2PS guarantees a stretch/movement area of 25%, preventing cracking or breaking of the window." Also new is Zwaluw Window Seal® Easy, which is distinguished by easy application. "Like Zwaluw Hybriseal 2PS, Zwaluw Window Seal Easy is excellent for water-based and acrylic paints. Also, both sealants are highly UV resistant. Because the elasticity of Zwaluw Window Seal Easy is slightly lower with 20%, it is easier to apply and smooth."

Silicone sealant for modular/prefab construction

With Zwaluw Window Seal® Plus, Bostik also supplies a silicone sealant for modular/prefab construction, according to Van Houwelingen. "The silicone sealant is easy to apply and smooth, after which the sealant remains permanently elastic. Thanks to rapid skin formation, no construction dust or dirt can adhere to the sealant. This keeps the joint nice and clean. Even during transport and assembly." 

Durable alternative to putty

Finally, Zwaluw Monustop® is specially developed for monumental glass, where people often want an alternative to putty, but with the familiar look and feel. "Zwaluw Monustop is suitable for all types of glass, has excellent processability and cures quickly, after which it is excellent for repainting with a water-based or synthetic paint. With this, we offer a suitable solution for every application."

If required, Bostik's glazing sealants are supplied with various sizes of glazing tape, glass blocks, cut-off water and various finishing timbers, which can be used to make a good sloping and draining sealant joint.   

Five steps

An average home has about 20 m² to glazing in the facade. This translates into some 80 m of sealing that must be applied correctly to maintain the indoor climate, protect against weather influences and prevent energy loss through air leaks. To support glaziers in this, Bostik recommends following the following five steps, for which it can of course also supply the right products and tools:

1) Pretreatment and adhesion testing;

2 Application of the self-adhesive PE glazing tape;

3) Applying the wedge-shaped support blocks;

4) Application of the elastic sealant;

5) Dry or wet fatten the excess sealant.