Ottocord PUR-H-B3 backer rod soft for interior joints 100 m
€15.95
- Formulated soft - easy to twist into narrow component joints
- Limits the joint depth and prevents three-flank adhesion of the sealant
- Seven diameters from 10 to 50 mm, 100 pieces of 1 m each
- Temperature-resistant from -30 to +70 °C per the manufacturer's data sheet
- 14 days right of withdrawal
- Expert advice: 02831 9167703 Mon–Thu 9–16, Fri 9–12 (CET)
- Specialist dealer in Kevelaer, Lower Rhine
Description
Ottocord PUR-H-B3 from OTTO is a backing cord made of extruded, open-cell polyurethane foam for backfilling joints indoors. It is formulated softer than the sister cord PUR-HS-B3 and can therefore be inserted easily into narrow component joints. It is supplied in seven diameters from 10 to 50 mm, in each case as 100 pieces of 1 m each – for professional tradespeople as well as for renovators with many joints.
Benefits at a glance
- Clean joint geometry: The cord limits the joint depth so that the sealant can be applied in the correct layer thickness.
- No adhesion to the joint base: The sealant adheres only to both joint flanks and can absorb movement instead of tearing at the joint base.
- Easy to insert: The soft formulation (compression hardness approx. 4–8 kPa) makes it easier to twist in even in narrow joints.
- Wide range of diameters: 10, 15, 20, 25, 30, 40 and 50 mm cover narrow connection joints up to wide component joints.
- Handy pieces: 100 lengths of 1 m instead of an endless roll – easy to transport and to process in portions.
Areas of application
- Backfilling connection and component joints in interior fit-out
- Preparing joints before filling with sealant
- Interior joints that remain free of wet exposure
Limits & notes
The cell structure is open-pored. According to the manufacturer the cord is therefore suitable neither for damp rooms nor for outdoors – a closed-cell PE backing cord is the right choice there. With building material class B3 to DIN 4102 the material is considered easily flammable; it is not intended for joints with fire protection requirements.
Application & tips
Choose the diameter about 20 % larger than the joint width so that the cord sits under pressure in the joint. Insert or twist the cord into the joint with pressure, ensuring an even depth, because it determines the thickness of the later sealant joint. Then close the joint with a suitable sealant.
Frequently asked questions
Which diameter do I need?
About 20 % more than the joint width: for an 8 mm joint the 10 mm cord fits, for a 16 mm joint the 20 mm cord.
Can I use the backing cord in the bathroom or outdoors?
No. Because of the open cell structure, according to the manufacturer it is intended only for interior joints without wet exposure.
Why do I need a backing cord at all?
It limits the joint depth and prevents the sealant from adhering to the joint base. This keeps the joint elastic and it does not tear.
What is the difference from the PUR-HS-B3?
The PUR-H-B3 is formulated softer and can therefore be inserted into narrow joints more easily.
How much cord is in a pack?
100 pieces of 1 m each, i.e. 100 m per pack and diameter.
Technical data
| Area of use: | Interior |
|---|---|
| Colour: | grey |
| Content: | 100 m |
| Material: | Polyurethane (PU) |
| Pack size: | 100 × 1 m piece |
| Version | |
|---|---|
| Size: | 10 mm |
| Technical data | |
| Base: | Polyurethane foam, extruded, open-cell |
| Bulk density: | approx. 16–20 kg/m³ (ISO EN 845) |
| Compression hardness: | approx. 4–8 kPa at 40 % deformation (DIN 53577) |
| Tensile strength: | > 80 kPa (DIN EN ISO 1798) |
| Elongation at break: | > 30 % (DIN EN ISO 1798) |
| Compression set: | < 50 % (ISO EN 1856) |
| Temperature resistance: | -30 to +70 °C |
| Building material class: | B3 to DIN 4102 |
| Use | |
| Field of use: | Indoors, without wet exposure |
| Application | |
| Diameter selection: | approx. 20 % larger than the joint width |
Data sheets
Data sheets and documents
All documents come unchanged from the manufacturer.
Manufacturer information
Manufacturer information pursuant to Art. 19 EU GPSR
Postal address
Hermann Otto GmbH
Krankenhausstr. 14
83413 Fridolfing
Germany
Electronic address info@otto-chemie.de
Information as of: 2026-09-17
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