Enquire about Dripstop Condensation Control

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Dripstop is a polyester fleece designed to reduce the risk of damage from dripping or running condensate on un-insulated single skin metal roofs in buildings with moderate to high humidity levels and poor ventilation.

The interlaced fibres of Dripstop slow the formation of condensate by insulating the sheeting and also prevent dripping from the underside of the roof by absorbing the moisture and holding condensate until it can evaporate.

Dripstop is available on Steadmans AS30 and AS13/3 profiles and is applied to the sheeting during the manufacturing process.

Condensation

When warm, moist air within a building comes into contact with cold surfaces there is a risk of condensation as the air cools and is unable to support the same amount of moisture. This commonly occurs on the underside of roofs of single-skin metal sheeting during the winter, but also on clear nights when night sky radiation substantially lowers the temperature of the roof surface.

The condensate can run down the roof and collect on or within the building fabric where it will cause rust, rot or damage to fittings, or may drip from the roof.

General guidance on avoiding condensation is provided in Part C of the Building Regulations and in BS5250:2011.

Benefits of Dripstop

  • slows the formation of condensate by insulating the sheeting
  • prevents condensate dripping from the underside of the roof
  • holds condensate safely until it evaporates by ventilation

Design Guidance

Dripstop controls condensation in an environment where it appears cyclically (it can’t prevent condensation).

Holding Capcity

Roof slope Water absorption
850g/m²
 45° 600g/m²
 90° 400g/m²

 

 For the fleece to work properly the building has to be adequately ventilated to allow the material to dry out between the cycles.

Where the internal environment houses livestock; ventilation requires detailed consideration, contact our Technical department for advice.

Steadmans recommends ventilation openings equivalent to 2.5% of the roof area at the eaves and 5% of the roof area at the ridge.

At the eaves ventilation is usually provided by a spaced cladding such as Yorkshire board or by the use of a ventilated sidewall sheet.

At the ridge fit a zed upstand with 160mm x 50mm ventilation openings at 200mm centres. Ridge flashing lap joints should be 150mm long and sealed with 9mm x 3mm NFRC Class A butyl sealant strip.

dripstop_vented_ridge

Eaves ventilation required = 2.5% of roof slope area

Ridge ventilation required = 5% of total roof area

DrainDripstop-1

Installation

Sheets lined with Steadmans Dripstop condensation control fleece are installed in the same way as standard sheets. Seal side laps with 6mm x 5mm NFRC Class A butyl sealant strip and stitch at 450mm centres with 23mm long self-drilling screws.

dripstop_side_lap

At mid slope sheet junctions form 150mm overlaps and seal with 6mm x 5mm NFRC class A butyl sealant strip. Steadmans AS30 Dripstop sheets are supplied with a 150mm cutback to the fleece to accommodate the lap joint. .

Steadmans AS13/3  Dripstop sheets cannot be supplied with a factory applied cut back so it is recommended that 150mm of fleece at the laps and 50mm at the eaves is melted with a heat gun on site to prevent moisture absorption at the drip edge.

Seal overlap joints with two runs of 6mm x 5mm NFRC Class A butyl sealant strip applied 10-15mm from each end of the lap and fixed with 25mm fasteners as shown below.

dripstop_fixing

Standard fixing position (3 fixings per metre)

dripstop_3_fixings

Lapped fixing position (5 fixings per metre)

dripstop_5_fixings

Eaves fixing position (4 fixings per metre)

dripstop_4_fixings

At the eaves Steadmans Dripstop sheets are supplied with 50mm cutback to prevent absorption at the drip edge.

Properties

Dripstop has good resistance to most acids, hydroxides and sulphides and does not support the growth of bacteria or mould.

Weight 110g/m2
Thickness 1.0mm
Colour White/black mix
Fire classification A2 – s1, d0

Maintenance

If necessary, Dripstop can be cleaned by pressure washing with water. To ensure the most efficient product performance it is recommended that Dripstop is washed annually.