Specification Clause
Nitoseal MB175 (formerlyPlastiseal)
Rubberised bitumen, mastic joint sealant, compatible with bitumen based membranes
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1.00Joint Sealant

1.01All joints must be prepared, and primed if required, in accordance with the manufacturer’s current technical data sheet.

1.02Preparation

The joint surfaces must be thoroughly dry and clean. Remove all laitance, curing compounds, form release agents, loose materials and any contaminating foreign matter from joint faces. Remove all rust, scale and loose surface coatings from metal surfaces. Remove any grease with Solvent 10.

In moving joints, the sealant must not be allowed to bond to the back face of the joint. Prevention of 3 sided adhesion is achieved by installing either a polyethylene bond breaker tape, or placing / pressure fitting a closed cell, polyethylene backing rod or filler board into the joint to support the internal back of the sealant.

All materials used in conjunction with the new sealant system, shall be approved by the sealant manufacturer.

1.03Primer

Not normally required. Refer to technical data sheet.

2.00Sealant

2.01The Sealant is to be flexible, based on a combination of bitumen and synthetic rubber, that dries to form a rubbery seal with excellent slump resistance. It is to be resistant to biodegradation, and suitable for sealing lap joints in gutters, pointing work in roofing , flashing details, and drainage channels where ponded water may reside.

The sealant may be applied in joints between minimum 5mm and maximum 40mm width. All moving joints should be designed so that total cyclic movement in tension and compression does not exceed 10% of the joint width at time of sealing. Total movement in shear should not exceed 20% of joint width at time of sealing.

The sealant shall exhibit the following properties:

Movement accommodation factor: / +/- 5% for butt joints (10% total)
+/- 10% for lap joints (20% total)
Drying time (solvent release): / Minimum 1 week @ 20oC (longer if lower temperatures or sealant depth greater than 20mm)
Chemical resistance: / Refer to Technical Data Sheet
Application temperature: / Minimum 5oC
Continuous service range: / minus 20oC to +80oC

2.02Nitoseal MB175 from Parchem Construction Supplies meets the performance criteria and is approved.

Parchem Construction Supplies 7 Lucca Rd Wyong NSW 2259
Phone: 1300 737 787
/ September 2009
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