FAQ and Support
Technical bulletins
Installation of window- and doorframes with Polyurethane Foam
Window and doorframes are made of materials such as wood, aluminum, steel and UPVC. Traditional window and doorframes are installed by using frame anchors. This method is time consuming and requires craftsmanship. Therefore, more often now, window and doorframes are installed using polyurethane foam. Using polyurethane foam can significantly reduce labour costs and produce higher insulation value. It is important to take into account the properties of polyurethane foam during the installation, to avoid damage and costs later.
Facade panel bonding
The use of HPL-facade panels has strongly increased against the classical facade panelling which was normally made of plywood. The choice for these new building materials is usually based on the fact they do virtually need no maintenance and give a nice result without painting.
Inspection, maintenance and repair of sealant joints
Durability of sealants under normal weather circumstances can vary from 5 to more than 30 years, depending the type. This means with good functioning and application of the sealant, replacement is only mandatory after several years. In this period, instances requiring repairs or early total replacement of sealants might occur.
Finishing of sealant joints
The following is important:
- Processing equipment
- Application method
- Finishing method
Joint dimensions and constructions
Joint structures are used in both the interior and exterior of buildings.
These include:
- Joints, e.g., between frame / wall
- Expansion joints, eg, between concrete slabs
Mirror bonding
As, for esthetical reasons, mirrors are mostly applied to walls and doors without any mechanical support, special adhesives are used to fasten these mirrors ”invisible” onto the supporting surfaces. Mirrors are sensitive products, because of which not every mirror can be glued with every glue onto every surface. It is evident that care has to be taken. The information given below will be helpful to achieve a good result.
Suitability and pre-treatment of surfaces
For an optimal functioning of a sealant joint it is of essential concern that the sealant will make a good bonding on the surface it is applicated to. Indeed if the bonding fails, the function of sealing partly fails. The strength of bonding between sealant and surface depends to: 1 Strength of surface. 2 Suitability of surface. 3 Pre-treatment of surface. 4 Situation of surface during application. 5 Tolerance of surface with the sealant applied. 6 Application of bonding primer. Furthermore, it is of course important that the sealant is applied in the correct manner.
How to determine the initial strength
The market for constructive sealants is fast growing. More and more mechanical fasteners are replaced by constructive elastic bonds. Constructive bonding has many advantages over mechanical fastening and very few disadvantages. High modules polyurethane and hybrid sealants are the most common sealants used for this purpose. Compared to mechanical fasteners these sealants are often stronger and don’t cause corrosion on metals. Other benefits of using these high module sealants: makes drilling unnecessary, reduces sound transmission and can also provide a watertight seal.
Airtightness of uPVC and aluminium windows
When uPVC and aluminium window frames are assembled in a new building or renovation project, Den Braven is able to provide a suitable solution to achieve compliance with current and new building regulations. Joint connections should be treated with high end products to fulfil the passive house regulations.
Damage to sealant joints by animals
Sealants used in construction and industry applications must provide a permanent seal between building materials. In normal conditions, combined with regular inspection and maintenance, joint sealants may function for many years. The durability of sealants in joints may be reduced severely by the impact of animals. In this technical bulletin the most common forms of damage by animals is discussed, including possible solutions to prevent and repair damage.
Syneresis & Silicones
Sometimes a small clear oily separation is visible when a cartridge is opened. This we call leaching.
Paint cracking in acrylic paints
Although in general acrylic sealants can be painted very well both with solvent based paints as well as water based paints (for instance acrylic latex) it is possible that the paint film on the acrylic joint can crack.
Tolerance of sealants with paint
In this we have two situations:
- Sealant applied to a layer of paint
- Paint applied to a sealant joint
Influence of temperature in storage and/or transport
In the technical documentation for of all Den Braven’s products the minimum shelf life after production is given as between +5°C and +25°C. When products are stored in higher temperatures this will shorten their shelf life. A maximum temperature of +45°C can be maintained. Above this temperature problems might occur. For instance, too much pressure may build up in canisters of PU foam. In neutral silicone sealants the chemical reactions can be changed.
Fungi resistance of sealants
Where products are used in wet areas like kitchens, bathrooms, swimming pools, abattoirs, cooling rooms, storage - and production rooms for food, fungal growth can occur. As a result of temperature, humidity, soap residue and traces of fungi in the air fungi can start growing on wet surfaces and is difficult to remove. This can happen on sealant joints. Fungi can develop at a humidity of 60% and grow even faster at higher humidity.
Chemical resistance silicones
With regards to the effects of solvents and industrial chemicals on silicone rubber, the following data has been complied: Silicones are chemically inert and are attacked by very few common materials. Among them are concentrated sulphuric acid, hydrofluoric acid and, after long term exposure, high pressure steam. Like any elastomer, silicone has a tendency to physically absorb those materials with a solubility parameter near its own. This absorption may cause the rubber to swell and to soften slightly. In a few applications, this volume increase is advantageous. For example, a silicone rubber gasket exposed to certain solvents will swell to form a tighter seal. The change undergone by silicone rubber in contact with an absorbed solvent is primarily physical. After the solvent has completely evaporated, the silicone rubber will return to its original physical properties.
Discoloration in sealant joints
Sealants are used in building and industrial applications in many places under various circumstances and on several substrates. It may occur that the sealant joints show discoloration after a couple of days or weeks. In general the joints can be considered as a reasonably colour stable product. The best colour stability can be achieved with the acetoxy curing silicone sealants and acrylic sealants. The neutrally curing Silicone sealants are more sensitive to yellowing, which in many cases is caused by contact with chemical vapours and fluids. In practice it seems that if discoloration of the sealant joint occurs, this most often is caused by local circumstances, which will be further illustrated below.
Glazing systems
This technical bulletin is addressing the Dutch market and gives in insight how to interpret and combine local regulations with this bulleting. Please familiarize yourself with local laws and regulations.
A well - constructed glazing system significantly influences the durability of the entire construction. There are standards in place for the execution and construction of glazing systems: NEN 3576 and NPR 3577. These standards indicate with what glazing systems they should be compliant, and how this can be achieved. For correct application, these standards should be consulted. (The Dutch standards can be obtained at Nederlands Normalisatie Instituut). This technical bulletin is intended as a compliment to these standards.