DB3.5 Internal Airtightness Membrane
£127.45 (inc. VAT £152.94)
Internal vapour control and airtight membrane
75m2 per roll
56 in stock (Available for Backorder)
PAVATEX DB 3.5 is used as an Internal vapour control and airtight membrane used in permeable roof and wall constructions. PAVATEX DB 3.5 is installed on the warm side of the thermal insulation. Gluing the membrane overlaps, connections and penetrations are completed using PAVATEX sealing products.
| Roll Width [m] | Roll Length [m] | Roll Area [m²] | Roll Weight [kg] |
|---|---|---|---|
| 1.50 | 50.00 | 75.00 | 9 |
| Weight | 9 kg |
|---|---|
| Dimensions | 1.5 cm |
FAQs
Frequently Asked Questions (FAQs) about PAVATEX DB 3.5 Airtight Membrane
What is PAVATEX DB 3.5 and what is it used for?
PAVATEX DB 3.5 is a high-performance internal airtight and vapour control membrane designed for use in vapour-open roof and wall constructions. It helps create a controlled airtight layer on the warm side of insulation to improve energy efficiency and prevent unwanted air movement.
Where should I install the PAVATEX DB 3.5 membrane?
The DB 3.5 membrane must be installed on the warm side of the thermal insulation in roof or wall structures. All joints, penetrations and overlaps should be sealed with compatible PAVATEX sealing products to ensure airtightness.
What are the key physical properties of the DB 3.5 membrane?
Each roll of PAVATEX DB 3.5 measures 1.5 m wide and 50 m long (75 m²) and weighs around 9 kg. It is made from a non-woven polypropylene fleece with a polyolefin copolymer coating, offering strength, shape stability and tear resistance.
How does the DB 3.5 membrane improve building performance?
By acting as a vapour control and airtight layer, this membrane reduces air leakage and helps maintain consistent indoor temperatures. This contributes to better thermal performance, reduced energy bills and a more comfortable internal environment.
Do I need special tools or tapes to install the DB 3.5 membrane?
Yes. For a correct installation, overlaps and joints should be connected draught-free and sealed using appropriate PAVATEX products, such as PAVAFIX 60, PAVATAPE 12 and PAVATAPE FLEX. On porous surfaces, priming with PAVAPRIM is recommended before taping.
Can PAVATEX DB 3.5 be used on floors or external applications?
Yes and No. The DB 3.5 membrane is specifically designed for internal vapour control and airtightness in breathable roof and wall constructions; it can also be used for airtightness on the warm side of suspended timber floors. It is not suitable for use externally, waterproofing or slab floor applications.
How should the membrane be stored before installation?
Store rolls either lying down or standing upright in a cool, dry place protected from sunlight and moisture to maintain the product’s integrity and performance quality.
Is the DB 3.5 membrane safe for indoor use?
Yes. PAVATEX DB 3.5 complies with standard health and safety requirements and does not contain substances harmful to health or the environment.
How do I ensure airtight connections at joints and penetrations?
Ensure that all overlaps, connections and penetrations are sealed with the correct PAVATEX airtight tapes and adhesives specified in the installation guide. This prevents air bypass and maintains the designed airtightness level.
What is the vapour diffusion resistance (Sd) value of DB 3.5?
The membrane’s vapour diffusion equivalent (Sd) is approximately 3, meaning it allows controlled movement of water vapour while providing a robust vapour control layer in internal assemblies.