J42 NBS ROOFING SPECIFICATION

Project:

Prepared for:

                            

J42 Single layer polymeric sheet roof coverings
To be read with Preliminaries/ General Conditions.
	 	TYPES OF COVERING

110	WARM ROOF COVERING

	•	Substrate  Exterior Grade Ply Wood 18mm thick minimum 
	- Preparation: Ensure decking is well secured with an even smooth, clean and dust free surface.  
	•	Roof covering system: Manufacturer: SIG Design and Technology, Mannheim House, 
 Gelders Hall Road, Shepshed, Leicestershire LE12 9NH.   
 Tel: 01509 505714. Fax: 01509 505475. 
           	 Email sales@sigdandt.co.uk Web: www.singleply.co.uk 

	Product reference: Rhepanol® fk System.
	- Lower protective layer (loose laid): Not required.
	- Vapour control layer: PE 1000 gauge	 
	- Insulation: Flat Board Approved by SIG Design and Technology
	- Separating layer (loose laid): Not required. 
	- Waterproof membrane: Rhepanol® fk 
Rhepanol® fk is a roofing membrane made from polyisobutylene (PIB), with a prefabricated self-sealing edge and an integrated synthetic fleece backing
	Rhepanol® fk Mechanically Fixed
With mechanical fastening the roof sealing is separated from the lower layers and components across the complete area. Movement of these layers and components can therefore not pass on stresses to the sealing, which is significant for the prevention of damage, especially on lightweight roofs. 
Rhepanol® fk is rolled onto mechanically fastened Gripfix strips, providing optimal wind load distribution and securing the membrane permanently to the roof. Fixing plan provided by SIG Design and Technology
Rhepanol is supported by BBA Certification for a life of 30 years, has Life Cycle Assessment and FM Approval

	Width: Roll width: 1.05m / 0.65m / 0.52m / 0.35m
	Roll length: 15m.
	Thickness: 2.5 mm including polyester fleece backing. 
	Colour: Grey.
	Weight: 2.6 / 2.7 / 2.8 / 2.9 / 3.0 kg/m²

           - Upper protective layer not required:

	•	Accessories: Consult SIG Design and Technology technical literature for details. 

PERFORMANCE
	 
210	ROOF PERFORMANCE

	•	Roof covering: Secure, free draining and weather tight.

220		AVOIDANCE OF INTERSTITIAL CONDENSATION: WARM AND INVERTED ROOFS

	•	Determine: Interstitial condensation risk of roof construction as recommended in BS 6229. 
	•	Basic design data:
		- Outdoor notional psychometric conditions, winter:
	Temperature: -5°C.
	Relative humidity: 90%.
	Vapour pressure: 0.36 kPa.
	Duration: 60 days.
	- Outdoor notional psychrometric conditions, summer:
	Temperature: 18°C.
	Relative humidity: 65%.
	Vapour pressure: 1.34 kPa.
	Duration: 60 days.
	
	- Indoor notional psychrometric conditions:
	Temperature: 20ºC. 
	Relative humidity: 70%.
	Vapour pressure: See technical data sheets. 
	•	Winter interstitial condensate:
	- Calculated amount (maximum): 0.35 kg/m². 
	- Calculated annual net retention: Nil.
	•	Vapour control layer: If calculated amounts of condensate exceed allowed amounts, provide a suitable membrane or sealed deck so that damage and nuisance from interstitial condensation do not occur.

225		AVOIDANCE OF INTERSTITIAL CONDENSATION: WARM AND INVERTED ROOFS

	•	Determine: Interstitial condensation risk of roof construction as recommended in BS5250 
		Annex D.
Vapour control layer if necessary provide a suitable membrane so that damage and nuisance from interstitial condensation do not occur.
230	INSULATION

	•	Requirement: Determine type and thickness of insulation and integral or separate overlay to satisfy the following criteria:
	- Thermal transmittance of the roof (maximum): 0.2 W/m²k. 
	- Compressive strength of insulation (minimum) at 10% compression: 60 kPa.
	- Finished surface: Suitably even, stable and robust to receive roof covering.
	- Insulation compliance: To a relevant British Standard, or Agrément certified.

240	ATTACHMENT Euro code 1(GB), Part 2-4 from May 1995

•	Requirement: Determine methods of attachment to resist wind loads. Provide for relative movement of materials and effects of vapour pressure. Do not reduce performance of Vapour control layer.
•	Wind loads: Calculate to BS 6399-2, Standard Method consult SIG Design and Technology for this information

		PRODUCTS	
330	TIMBER TRIMS, ETC

	•	Quality: Planed. Free from wane, pitch pockets, decay and insect attack except ambrosia beetle damage.
	•	Moisture content at time of covering (maximum): 22%. 
	•	Preservative treatment: As recommended for purpose by waterproof covering manufacturer.

334	FIXINGS FOR INSULATION

	•	Type: Tube washer and Fixing 
•	Manufacturer: SIG Design and Technology, Mannheim House, Gelders Hall Road, Shepshed, 
		Leicestershire LE12 9NH. Tel: 01509 505714. Fax: 01509 505475. 
		Email: sales@sigdandt.co.uk Web: www.singleply.co.uk.
           - Product reference: To be determined by roof build up
	
335		Bituminous reinforced VCL with an encapsulated impervious aluminum core sand faced  
345	PERIMETER TRIMS

	•	Type: 0.6 mm galvanized steel with 0.5 mm unreinforced membrane laminate.
	•	Manufacturer: As roof covering.
		- Product reference: Rhepanol Drip Trim.
	•	Colour: Light grey.
	•	Size: As required.

355		MECHANICAL FASTENERS, WASHERS, PRESSURE PLATES,ETC

	•	Type: Plate Washer and Screw.
	•	Manufacturer: SIG Design and Technology, Mannheim House, Gelders Hall Road, Shepshed,      
	Leicestershire LE12 9NH. Tel: 01509 505714. Fax: 01509 505475. 
	Email: sales@sigdandt.co.uk Web: www.singleply.co.uk.

420		RIGID URETHANE FOAM WARM ROOF INSULATION

•	Type: Rigid polyisocyanurate foam (PIR) roof board: To BS 4841-3.
•	Manufacturer: Recticel
•	Type: Eurodeck Foil/fFoil 
A CFC/HCFC-free rigid urethane insulation board faced on both sides with bonded wet lay coated glass fibre tissue, designed for use beneath mechanical fastened single-ply roofing.
•	Type: Glass fibre foil faced rigid urethane insulation board.
•	Density: 32-48 kg/m³.  
•	Thickness: As required. 
•	Facing: Foil.
480	PIPE COLLARS

	•	Manufacturer: As roof covering.
		- Product reference: Rhepanol f.
	•	Size: See Technical details.

EXECUTION GENERALLY
510	ADVERSE WEATHER

	•	General: Do not lay membrane at temperatures below 5°C or in wet or damp conditions unless effective temporary cover is provided over working area.
	•	Unfinished areas of roof: Keep dry and protect edges of laid membrane from wind action.
520	INCOMPLETE WORK

	•	End of working day: Provide temporary seal to prevent water infiltration.
	•	On resumption of work: Cut away tail of membrane from completed area and remove from roof.
	 	SUBSTRATES/ VAPOUR CONTROL LAYERS/ WARM ROOF INSULATION
610	SUITABILITY OF SUBSTRATE

	•	Surfaces to be covered: Firmly fixed, clean, dry, smooth, free from frost, contaminants, voids and protrusions.
	•	Preliminary work: Complete, including
	- Grading to correct falls.
	- Formation of upstands, kerbs, box gutters, sumps, grooves, chases and expansion joints.
	- Fixing of battens, fillets and anchoring plugs/ strips.
	•	Moisture content and stability of substrate: Must not impair integrity of roof.
650       LAYING VAPOUR CONTROL LAYER

	Setting out: 
SIG Design and Technology Vapour control layer fk is applied with a seam overlap of 10cm, with the seams being sealed with connection or seam tape.
The vapour control layer must be taken up and flashed at connections and cappings, at roof penetrations it must be flashed.

680	LAYING WARM ROOF INSULATION

	•	Setting out: 
	- Long edges: Fully supported and running at right angles to troughs in metal decking. 
	- End edges: Adequately supported.
	- Joints: Butted together.
	- End joints: Staggered.
	•	Attachment: Fixed.
	•	Completion: Boards must be in good condition, well fitting and firmly fixed.

		
WATERPROOF COVERINGS/ ACCESSORIES

730	WELDED JOINTING

	•	Laying: Loose lay, do not wrinkle or stretch.
	•	Side and end joints:
- Laps (minimum): Lap side joints not less than 50mm ensuring that the water will drain over and not into them.
Clean the lower membrane below the overlap with Rhepanol Solvent Welding Agent. If the weather is cool or humid the seams should be cleaned section by section and mated before the solvent has evaporated.
Remove the protective paper from the sealing edge and immediately apply pressure to the seam with the Rhepanol hand roller (taking care to avoid folds or pleats). The seams should then be firmly rolled with the Rhepanol universal roller.
To prevent capillary action the corner of the lower roofing membrane is cut off before removal of the protective paper.

740	SEALING OF CROSS JOINTS:

A strip of Rhepanol cover tape, 100mm wide and long enough to overlap both seams by 50mm is cut and the corners rounded off. The cross joint is then cleaned with the Rhepanol Solvent Welding Agent.
To prevent capillaries a bead of Rhepanol paste (approx. 4mm thick) is applied to the membrane's edges, slightly longer than the width of the cover tape.
	Apply the Rhepanol cover tape over the joint and allow to protrude 50mm to either side.
With the Rhepanol hand roller, and without stretching the tape, roll the tape at the T joint to and against the seam to remove all air bubbles whilst ensuring the paste is not squeezed from under the tape. Confine the paste by dabbing with moist thumbs.
	- Preparation: Clean and dry surfaces for full width of joint.
	- Sealing: Weld together.
	•	Condition at completion: Fully sealed, smooth, weatherproof and free draining.
	•	Accessories: As per SIG Design and Technology Technical Details.
760	PERIMETER OF MEMBRANE

	•	General: Secure membrane at roof edge conditions, changes of plane, kerb flashings, upstands to roof lights, etc. with mechanical fasteners.

775	PERIMETER DETAILS FOR ELASTOMERIC MEMBRANES

	•	Upstands, edge trims, drips, kerbs, etc: Preformed from waterproof membrane material.
	•	Reinforcing strip: 
	- Lay at edge of horizontal roof plane. 
	- Securing: Mechanically fasten.
	•	Roof membrane: Dress over perimeter profiles.
	- Sealing: Bond to substrate and to secured perimeter reinforcing strip.

	785	ROOF PENETRATIONS THROUGH ELASTOMERIC MEMBRANES

	•	Roof membrane: Cut around penetrations.
	•	Flanged sleeve: 
	- Type: Form from roof membrane complete with base flange. 
	- Installation: Dress over and around penetration. 
	- Seating: Flush to roof membrane.
	- Roof membrane overlap to flange (minimum): 75 mm beyond fasteners.
	- Sealing: Solvent weld.

	 COMPLETION
910	INSPECTION

	•	Interim and final roof inspections: Submit roof covering manufacturer's reports.
920	ELECTRONIC ROOF INTEGRITY TEST: IF REQUIRED

	•	Testing authority: The roofing contractor. 
	•	Timing of test: Prior to completion. 
	•	Condition of roof prior to testing: 
	- Waterproof membrane complete to a stage where integrity can be tested.
	- Surface: Clean.
	•	Test results and waterproof integrity certificate: Submit on completion of testing.
	940	COMPLETION

	•	Roof areas: Clean.
	- Outlets: Clear.
	•	Work necessary to provide a weather tight finish: Complete.
	•	Storage of materials on finished surface: Not permitted.
	•	Completed membrane: Do not damage. Protect from traffic and adjacent or high level working.