PU foam strip Ø 30mm (open cell)

Joint foam strip Ø 30mm made of soft polyurethane

For width joints up to 25mm ✓ UV-resistant ✓ TOP quality ✓

Our foam strips in 30mm are made of open-cell polyurethane and are offered as metre lengths at favourable graduated prices. The grey joint strips, which are mainly used as filling material for expansion joints and wall connection joints, are UV-resistant and are therefore suitable for joints indoors as well as for sealing joints outdoors. The soft, elastic foam strips are very easy to process and can be easily inserted into the intended joint without the use of any tools.

The 30mm diameter foam strip is perfect for limiting the joint depth for joints with a width of at least 20mm up to a maximum of 25mm. To achieve sufficient thickness of the sealant within the joint, the depth of the joint should be at least 50mm. However, a foam strip not only ensures the ideal joint thickness, which is significant for the elasticity of the sealant after vulcanisation, but also reduces the risk of undesired three-flank adhesion, which definitely affects the durability of a joint sealant.

Scope of delivery:
• 1 x foam strip Ø 30mm open cell 1000mm length

TIP: Despite the rather large diameter, the 30mm PU foam strips can be cut to size very easily with sharp scissors or a cutter knife.

Properties of the PU foam strip in Ø 30mm

The PU foam strips made of open-cell polyurethane have a good chemical resistance for all materials that are common in the construction and industrial sector. Only against concentrated acids and alkalis, as well as against petrol, is the resistance to be classified as average, which does not represent a significant restriction for use as a filler material for joints that are later to be sealed with a sealant. An actual limitation, however, are joints that are permanently under a high load, for example due to water pressure or mechanical pressure. The foamed material is flexible and soft and would not provide sufficient resistance to continuous mechanical pressure, so that the joints could tear. For joints that are subject to permanent mechanical pressure, closed joint strips made of polyethylene should be used instead.

The flexibility of the joint strips, which is typical of foamed polyurethane, on the other hand, has the decisive advantage that they can be used very easily, especially in joints with deviating, varying joint widths. By simply compressing the soft material, the foam strip can thus also be inserted in joint areas with a narrow width, even if this is less than the recommended width of 20mm-25mm. In addition, the open-cell structure of the 30mm foam strip has very good insulation values, which is particularly effective for the thermal insulation of joints in outdoor areas. In order to be able to use our foam strips for joints indoors without hesitation, we only offer CFC- and HCFC-free joint strips, which are considered physiologically neutral.

Technical data of the PU foam strip in 30mm

• Material: Polyurethane
• Colour: Grey
• Diameter: 30mm
• Recommended joint width: 20mm - 25mm
• Recommended joint depth: min. 50mm
• Density: 0.125g/cm³
• Shore hardness: 20 - 40
• Shrinkage hardness: min. 150 KPa according to DIN 53571
• Elongation at break: min. 150% according to DIN 53571
• Compression set: 25% - 35% in accordance with DIN 53572
• Temperature resistance: -30°C - +60°C
• Ageing resistance: Excellent
• UV resistance: Sufficient
• Water resistance: Sufficient
• Chemical resistance: Sufficient

NOTE: Foamed PU strips are moderately resistant to petrol and concentrated acids or alkalis.

Processing of our foam strip in 30mm diameter

Especially for joint widths of more than 20mm, the use of a foam strip as a filling material makes perfect sense. With such high joint widths, without limiting the joints, it is almost impossible to select the thickness of the joint through the sealant application so that it does not turn out too high. For wall joints, the joint thickness should be about 50% of the joint width and have a two-flank adhesion to ensure the elastic properties of the joint. For load-bearing floor joints, on the other hand, a joint thickness of 60%-100% is recommended, depending on the joint width and load. With a thick foam strip in 30 mm diameter, even such large joints can be limited to the millimetre. This not only ensures the elasticity of the joint, but also counteracts excessive sealant consumption, which could be enormous with such wide joints. The 30mm diameter foam strip can be used for joints with a minimum depth of 50mm and joint widths between 20mm and 25mm. However, the soft, foamed material can be easily compressed to fill joints with a smaller width in places without having to use a thinner joint strip. The foam strip is inserted either very simply with the finger or with a joint strip roller, which can also be used to precisely adjust the subsequent joint thickness.

PU foam strips have very good insulation values due to their open-cell structure. If the foam strips are used for this purpose, care should be taken to ensure that processing takes place without too much expansion. The foam strips contract back to their original length over time, so that if they are stretched too much, a gap can form behind the sealant, which has a detrimental effect on the insulating properties. In addition, the lack of delimitation of the joint in places, due to the gaps created, can reduce the load-bearing capacity of the cured joint.

Application examples:
• Foam strips are ideal for limiting the perfect joint thickness for wide joints up to 25mm
• Faulty three-flank adhesion is virtually eliminated when using foam strips
• PU foam strips can be used with all conventional sealants, e.g. silicone
• The 30mm thick strips have a positive effect on the thermal insulation of exterior joints
• The use of foam strips counteracts excessive consumption of sealant

The processing of sealants such as silicone, acrylic or MS polymers should be carried out in a temperature range between +5°C and +40°C. The same temperature range also applies to the processing of our round cords made of polyurethane, which are inserted into the joints before sealing. It is also important to ensure that the round cords are processed in a dry state and do not become wet before the sealant is applied, e.g. due to rain. This is because absorbed moisture may not be able to dry quickly enough after the joint has been sealed.

NOTE: Foam strips made of open-cell polyurethane enjoy dry storage at temperatures between +5°C and +25°C.