J42 NBS ROOF 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: Concrete Deck with bituminous felt and insulation. 
- Preparation: remove loose material and prepare surface to receive Bitumen Primer
  
	•	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: Bituminous. 
	- Insulation: Tapered bonded with Adhesive U.
	- Separating layer (loose laid): Not required. 
	- Waterproof membrane: Rhepanol® fk bonded
Bonding Rhepanol® fk roofing membrane using Rhepanol®-Adhesive 90, ensures the maximum possible mobility of the roofing membrane. 
Rhepanol® fk is a roofing membrane made from polyisobutylene (PIB), with a prefabricated self-sealing edge and an integrated synthetic fleece backing. 
	Roll width: 1.05m 
	Roll length: 15m
	Thickness: 2.5 mm including polyester fleece backing. 
	Colour: Grey.
	Weight: 2.6 kg/m²
	- Upper protective layer (loose laid): Not required
	The system is installed by an approved SIG Design and Technology contractor, see attached list. 

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

	•	110mm FDT Aluminium edge trim profile to parapet.  

PERFORMANCE
210	ROOF PERFORMANCE

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

220		 VAPOUR CONTROL LAYER
 
	 •	 Interstitial condensation risk of roof: Determine as recommended in BS 6229. 
	 Modify calculation method to conform to BS 5250.
	 •  		 Basic design data:
-	Outdoor notional psychrometric 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.
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 Eurocode 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.
	- Basic wind speed (Vb): See attached fixing specification.
	- Altitude factor (Sa): See attached fixing specification.
	- Direction factor (Sd): See attached fixing specification.
	- Seasonal factor (Ss): 1.
	- Probability factor (Sp): 1.
	- Terrain and building factor (Sb): See attached fixing specification.
	- Size effect factor (Ca): 1.
	- External pressure coefficients (Cpe): See attached fixing specification.
	- Internal pressure coefficients (Cpi): See attached fixing specification. 	

PRODUCTS

325	ADHESIVE For bonding insulation boards

	•	Type: Synthetic bonding adhesive.
	•	Manufacturer: SIG Design and Technology.
          -  Product reference: Adhesive U.
325b	ADHESIVE for bonding membrane

	•	Type: Synthetic bonding adhesive.
	•	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®-Adhesive 90.

330		TIMBER FOR 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: Not required. 
340	PREFORMED SLEEVES, TRIMS, ETC

•	Type: Flanged sleeve formed from roof membrane.
•	Manufacturer: As roof covering.
-	Product reference: Rhepanol f or Rhenofol C.
•	 Colour: Light grey.
•	 Size (minimum): To suit project details.
345	PERIMETER TRIMS

	•	Type: Extruded aluminium.
	•	Manufacturer: As roof covering.
	Product reference: Aluminium roof edge trim
	•	Colour: Silver metal grey.
	•	Size: To suit detail.
355	MECHANICAL FASTENERS, WASHERS, PRESSURE PLATES, ETC

	•	Type: Tube 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.

385	VAPOUR CONTROL LAYER

	•	Type: Bituminous VCL with an encapsulated impervious aluminum core Sand finished to be used in conjunction with the Bitumen Primer
          •	Water vapour resistance: >1000 MN.s/g	

420     RIGID URETHANE FOAM WARM ROOF INSULATION

•	Type: Rigid polyisocyanurate foam (PIR) roofboard: To BS 4841-3.
•	Manufacturer: Gradient
-	Product reference: Power Deck F Tapered Insulation
A CFC/HCFC-free rigid urethane insulation board faced on both sides with bonded wet lay coated glass fibre tissue, designed for use beneath fully adhered single-ply roofing using solvent based adhesives.
 Type: Glass fibre tissue faced rigid urethane insulation board.
•	Density: 32-48 kg/m³. 
•	Thickness: As required.
•	Facing: Glass tissue.

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.
670	LAYING VAPOUR CONTROL LAYER
 
	•	Laying: Sheets loose, flat and smooth.
	•	Side and head laps: 50 and 75 mm respectively. Seal using materials and method recommended by membrane manufacturer.
	•	Upstands, kerbs and other penetrations: Enclose edges of insulation. Fully seal at abutment by bonding or taping.	    

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.
	•	Mechanical fixing: Determined by contractor. 
          •	Completion: Boards must be in good condition, well fitting and firmly fixed.
		WATERPROOF COVERINGS/ ACCESSORIES

720		ADHESIVE BONDING OF WATERPROOF MEMBRANE

	•	Laying membrane:
	- On a continuous even coating of adhesive.
	- Do not wrinkle or stretch.
	•	Attachment: Roll out the Rhepanol fk and overlap the seams by at least 50mm and fold back half of each sheet along its length. Apply Rhepanol Adhesive 90 in beads of 10mm deep and 100mm apart using the Rhepanol applicator trolley. Allow adhesive to tack off for 10 minutes. Fold back the Rhepanol fk, roll with universal roller to ensure fleece is embedded into the adhesive, and seal the joints.
	•	Surface condition at completion: Fully sealed, smooth, weatherproof and free draining.

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, curb 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.