Roof Ventilation Literature - Issue C.indd

oof ventilation

oof ventilationcomplete roof ventilationsystems from ManthorpeventilationrequirementsOne of the major problems experienced bytoday’s energy conscious society is the build upand subsequent effects of significant levels ofcondensation in the roof space. This problem iscaused by the lack of adequate ventilation to theroof void.BS 5250: 2002 ‘Code of practice for controlof condensation in buildings’ incorporatingAmendment 1: 2005 is now cited as the industrystandard regulation throughout the UK andIreland concerning roofing ventilation, insulationand lining.Condensation is encouraged by the widespread use of insulatingmaterials, central heating and double glazing. Along with thereduction in natural ventilation, the temperature differential betweenthe dwelling areas and the cold space is increased. The warm,internal air carrying high levels of water vapour is naturally drawn,by the process of convection, to the cold areas of the buildingincluding the roof void.Here, if there is insufficient ventilation, condensation occurscausing rotting timbers, rusting and weakening of metal fixings,felt damage and mould growth. Items stored in the loft are oftenrendered useless and the general outcome involves significantexpenditure to rectify the problems.To eliminate this unnecessary cost, Manthorpe manufactures arange of quality roof ventilation products which are suitable fornew build and refurbishment situations.Products available include:• Continuous soffit and fascia vents• Cross flow panels and lap vents• Tile and slate vents• Abutment and dry fix ridge ventilating systemsFor a roof pitch more than 15°,10,000mm²/m is needed atthe eaves or low level. Pitchesabove 35° or where the roofspan exceeds 10m, an additional5,000mm²/m at the ridge or highlevel is required.For roof pitches of 15° or less,25,000mm²/m is required at theeaves or low level to ensure across flow of ventilation.Dormer windows, fire barriersand pitch changes for example,create separate voids within theroof space. Ventilation must bemaintained to these areas athigh and low level as illustrated.Mono-pitched roof details requirea 5,000mm²/m ventilation gap athigh level, whilst maintaining a10mm or 25mm gap at low leveldepending on the roof pitch.5*Roof Pitch Over 15°10 10255Roof Pitch Below 15°5*When the pitchexceeds 35° orspan exceeds 10m25 2550mmmin gap50mmmin gap25 Flat Roof Dormer25*10mm or25mm to suitthe pitch10/25*5Mono Pitch Roof

eaves ventiltation solutionsG1280 Felt Support TrayABCG1200N/G2500N Over Fascia VentilatorA G500 Roll PanelB G1280 Felt Support TrayC G1200N/G2500N Over Fascia VentsImage shown is the G1290 Universal Roof Vent Pack.The Manthorpe G1290/G1292 6 metre Ventilation Packprovides a practical and cost effective solution for roof ventilationrequirements. The pack consists of a 6 metre run of Manthorpeover fascia ventilator, roll panel and felt support tray, all theproducts supplied in the pack are designed to comply withBuilding Regulations and British Standards. Available for 10mm²and 25mm² ventilation situations.G500/G502 Continuous Roll PanelsThe G1280 Felt Support Tray prevents roofing felt sagging at theeaves, where water could collect and cause the felt to rot.Designed with a smooth leading edge to fit on the top of thefascia board, the slimline over fascia ventilator discreetly ensuresa positive passage of airflow into the roof space between the feltand the fascia board making it ideal for new build and re-roofingsituations. The tray will fit any rafter centres and provides supportfor the roofing felt, eliminating the problem of rotting felt by stoppingit sagging and retaining water at the eaves.The G1200N gives 10mm² continuous airflow while the G2500Nprovides 25mm² continuous airflow and is also suitable for use inflat roof abutment situations.The Continuous Roll Panel Eaves Ventilator G500provides a simple and economical solution to the problemsof eaves ventilation. Suitable for 400mm, 450mm and 600mmraft centres, the panel has vertical strengthening ribs and issuitable for new build situations. Its flexibility makes it suitablefor refurbishment where rafter centres are not consistent orunknown. A double width version, the G502, is suitable foruse with extra thick insulation.Both the G1200N and G2500N are produced in 1 meter lengthsto suit market demand. Products are robust enough to be usedwith any/all Roof Tiles no matter what profile or if fitted with plaintiles and/or slates. Designed with clear fixing points both versionsof the Manthorpe Over Fascia vent come complete with flyscreenand will not crush or distort whilst fitting. The G2500N has beendesigned with a low profile enabling product to be easily fittedand minimising the need to have to trim down fascia boardsprior to fixing.

G1281 Refurbishment Felt Support TrayG800/G825 Continuous Soffit VentilatorG1275 Eaves Comb FillerG700 Circular Soffit VentilatorThe G1281 Refurbishment Felt Support Tray prevents feltsagging at eaves level and subsequent pooling of water.The G1281 is simple to fit in new build or refurbishmentsituations and eliminates the need to strip a large section ofthe roof to replace old felt. This product is suitable for use withmany roof coverings, including breather membranes. The supporttray should be positioned on top of the fascia boards and securedto the roof trusses, overlapped by minimum of 150mm. It shouldbe pushed under existing felt in refurbishment situations or in newbuild situations felt should be dressed over the tray.The G1275 Eaves Comb Filler is designed to prohibit entry ofbirds and large insects below the eaves of profiled tiles.The G1275 is designed with flexible fingers that adjust to fillthe gaps left when using profiled tiles eliminating the needto make or buy expensive purpose made profiled fillers.The product runs continuously along the top of the fasciaboard above the felt and is nailed into position through the fixingholes provided.The G800/825 Continuous Soffit Ventilators are designed toprovide the solution to roof ventilation where a traditional fasciaboard detail is specified.Manufactured in UPVC section, it is screwed onto the fascia andsecurely supports the soffit board which is inserted into the selfretaining mouth. The airflow passage consists of evenly spacedslots specifically sized to prohibit large insects gaining access, butwide enough not to be blocked by debris.A Continuous Sloping Soffit Ventilator product code G821 isavailable for sloping eaves details. Low Pitch and Flat Roof SoffitVentilators product codes G826 and G827 are also available.The G700 Circular Soffit Vent is designed to be fitted to thesoffit board prior to installation for new build situations.The G700 can also be easily retro-fitted into existing soffit boards.Standard fixing for this product is a simple push twist action into a70mm hole drilled in the soffit board. The airflow passage consistsof evenly spaced slots specifically sized to prohibit large insectsgaining access but wide enough not to be blocked by debris,paint or water droplets.

G400/G450/G600/G620 Cross Flow Eaves PanelG435/G645 Refurbishment Eaves Panel VentilatorG405/G455/G605/G625 Cross Flow Fly Screen Eaves PanelG630 Felt Lap VentilatorG405/G455 style shown leftG605/G625 style shown aboveThe Cross Flow Eaves Panel comprises rigid vacuum formedtrays designed to provide an air passage between the roof felt andloft insulation to enable ventilation of the roof space.Sizes are available to encompass the majority of rafter centres.Manthorpe provides a range of rigid, flat pack, vacuum formedpanels designed for an easy fix for open eaves or cottage styleeaves. The panels include a 4mm fly screen.The G400/G450/G600 range provides 10mm² of airflow througheach panel which are designed to suit 400mm, 450mm and600mm rafter centres respectively. In addition to this rangeManthorpe produces a G625 product which provides 25mm²airflow per panel for use with 600mm rafter centres.The range of Cross Flow Fly Screen Eaves Panels productcodes G405/G425/G605/G625 have the addition of a series ofevenly punched holes and slots specifically designed to prohibitthe entrance of large insects but wide enough not to be blockedby debris, paint or water droplets. These panels are ideally suitedto open eaves and cottage style eave details.The G435 and G645 Refurbishment Eaves Ventilator Panels aredesigned to be used in refurbishment situations and are fitted fromwithin the roof space.Their flexibility allows them to fold to accommodate various roofpitches. By tucking the insulation well into the fold of the ventilatormaximum airflow is achieved. Check product suitability withinsulation level required.The G630 Felt Lap Vent is a refurbishment product designed toincrease the amount of ventilation into existing roof spaces.The G630 is usually fitted retrospectively to properties withadditional loft insulation recently installed, however the Felt LapVent will help to combat the problem of condensation build upin any roof space with a lapped felt/membrane construction. Theproduct can be easily installed by one person in joist openingsfrom 400mm to 600mm wide to provide 3,000mm² of airflow perunit. Please see fitting instructions and technical sheets regardingthe specific roof ventilation requirements.

tile ventsGTV-DR Double Roman VentGTV-NP Non-Profile Ventslate ventsGRSV30-25/45 Slate VentsGTV-CS Castellated VentGTV-DP Double Pantile VentGRSV30-25R/45R Refurb Fast-Fit Slate VentsThe Manthorpe range of In-Line Tile Ventilators are designed toprovide roof space ventilation, or an outlet for ventilation ductingthrough large format concrete roof tile coverings. The range of fourprofiles are universal in design and are compatible with all majorUK and Irish tile makes.The tortured path and in line design gives a discreet, weatherproof 10k mm² airflow path through the roof covering with therecommended 4mm spaced grill openings to prevent the entry ofdebris and large nesting insects.Available in a range of four colours to suit most tile types, the ventsare quick and easy to install, taking the place of a single tile withno need to cut the battens.GTV-AD Flexi Pipe AdaptorIf the product is to be used withmechanical extraction, soil stackor vent pipe termination, then theGTV-AD Flexi Pipe Adaptor andone of the GRPA Flexible Piperange should be used.The GRSV30-25 Slate Vent is designed to fit standard size600mm x 300mm slates, but this can also be cut down to a smallersize of 500mm x 250mm. The GRSV45 works with random slateswith a base size of 600mm x 450mm.All sizes of slate vent allow 10,000mm² air flow per unit, providingan unobtrusive, economical, high or low level roof ventilator.Manufactured from UV stabilised durable polypropylene, thevents have an integral insect grille and oval connection spigotfor mechanical extraction. Manthorpe’s slate vent has provedoutstanding in independent wind tunnel performance tests.The fast fit refurb vents GRSV30-25R/45R, without the ventspigot on the base, make retro-fitting into existing surroundingslates easier. It is simply slid between natural or man made slatesalready in position with no need to cut battens.GRPA/GRPA2/GRPA3 Flexible PipesThe GRPA flexible pipe provides a quick andeasy connection between the slate vent and 4"soil pipes or ventilation ducting systems.The extra length GRPA2 makes connectionsacross a longer distance even easier, while theGRPA3 allows a simple 4" to 3" pipe reduction.

abutment ventilationG1105 Abutment Flash Ventventilated ridge solutionsGDRR Roll-Out Dry Fix Ridge SystemGDR-T SmartRidge - Dry Fix Vented Ridge TileManthorpe designers have developed a revolutionary method forventing abutment roof details which takes the fuss out of fixing.The G1105 Flash Vent is a simple roll-out flexible sheet systemwhich provides a weather-tight solution to the need for a continuous5mm² airflow at roof abutment details.Manthorpe’s Research and Development team has addressed theneed for a flexible and effective system by incorporating a series ofnodules into the design on both sides of the flexible vent roll. Thisnot only provides the required airflow but includes an integral flyscreen and maximises support of the lead.The G1105 Flash Vent is economical and easy to install as it isformed from just one main component. It is supplied in a handybox dispenser with no need for specialist fixing tools.Manthorpe’s G1105 has been independently wind tunnel testedfor weather tightness and can be used over profiled tiles, nonprofiled tiles and slates without compromising its effectiveness.Two widths can also be joined together to fit any length of lapbetween the lead and the tiles.The Manthorpe Roll-Out Dry Fix Ridge is a mechanically fittedsystem which securely fixes the ridge tiles onto a roof. The GDRRsystem provides 5,000mm²/m ventilation to the roof void throughthe vent roll, the equivalent to a continuous 5mm gap.The dry fix system means there is no need for mortar, making thejob of fixing the ridge quick, easy and clean, as well as making itpossible during frosts and other adverse weather conditions. Thesystem is compatible with most makes of concrete half-round andangled ridge tiles and most slate, flat concrete and profiled tiles. Asingle box provides all of the components required for a ridge runapproximately 6 metres in length (excluding the ridge tiles).The SmartRidge Dry Ridge Tile System is a mechanically fixedtile designed to replace clay and concrete ridge tiles with a plasticmoulded part.The GDR-T interlocking system makes the tiles very easy to fit and,when completed, ensures an extremely secure finish.A patented double comb prevents entry of wind-driven rain andbirds, while a 4mm fly screen provides 5,000mm 2 /m of continuousventilation into the roof space at ridge level. The textured finish,available in Slate Grey, Dark Brown and Terracotta, is virtuallyindistinguishable from traditional clay and concrete tiles.

Product Specification GuideProduct ReferenceFreeAirflow mm 2 Size MaterialIntegralInsect Grille Colour BoxQtyG500 Continuous Roll Panel 10/25,000 325mm wide PVC Black 12LMG502 Continuous Roll Panel 10/25,000 650mm wide PVC Black 12LMG600 Cross Flow Panel 10,000 450mm wide PVC Black 50G620 Cross Flow Panel 25,000 450mm wide PVC Black 50G625 Cross Flow Fly Screen Panel 25,000 450mm wide PVC Black 50G450 Cross Flow Panel 10,000 350mm wide PVC Black 50G400 Cross Flow Panel 10,000 350mm wide PVC Black 50G605 Cross Flow Fly Screen Panel 10,000 450mm wide PVC Black 50G455 Cross Flow Fly Screen Panel 10,000 450mm wide PVC Black 50G405 Cross Flow Fly Screen Panel 10,000 450mm wide PVC Black 50G435 Refurbishment Panel 10/25,000 250mm wide PVC Black 50G645 Refurbishment Panel 10/25,000 250mm wide PVC Black 50G1280 Felt Support Tray - 625mm long PVC Black 50G1281 Refurbishment Felt Support Tray - 1.5m long PVC Black 10G1290 Ventilation Pack 10,000 6m long - 6LMG1292 Ventilation Pack 25,000 6m long - 6LMG1200N Over Fascia Ventilator 10,000 1m long Polypropylene Black 20G2500N Over Fascia Ventilator 25,000 1m long Polypropylene Black 20G1275 Eaves Comb Filler - 1m long Polypropylene Black 50G630 Felt Lap Vent 3,000 275 x 193.5 x 19mm Polypropylene White 50G800 Soffit Strip 10,000 2.44m long UPVC White/Brown/Black 10G825 Soffit Strip 25,000 2.44m long UPVC White/Brown 10G821 Sloping Soffit Strip 10,000 2.44m long UPVC White/Brown 10G826 Soffit Strip 25,000 3.1m long UPVC Brown 10G827 Soffit Strip 25,000 2.44m long UPVC White/Brown 10G700 Circular Soffit 2,150 70mm dia. Polypropylene White/Brown/Black/Golden Oak 50GTV-DR Double Roman Tile Vent 10,000 418 x 328mm UPVC Grey/Terracotta/Brown/Antique Red 4GTV-NP Non-Profile Tile Vent 10,000 418 x 334mm UPVC Grey/Terracotta/Brown/Antique Red 4GTV-CS Castellated Tile Vent 10,000 418 x 332mm UPVC Grey/Terracotta/Brown/Antique Red 4GTV-DP Double Pantile Vent 10,000 418 x 332mm UPVC Grey/Terracotta/Brown/Antique Red 4GRSV30-25 Standard Slate Vent 10,000 600x300/500x250mm Polypropylene Black 10GRSV30-25R Refurbishment Slate Vent 10,000 600x300/500x250mm Polypropylene Black 20GRSV45 Random Slate Vent 10,000 600 x 450mm Polypropylene Black 5GRSV45R Refurbishment Slate Vent 10,000 600 x 450mm Polypropylene Black 10GTV-AD Flexi Pipe Adaptor 8,800 236 x 243mm HIPS Black 10GRPA Flexible Pipe 8,000 455mm long Polyethylene Black 10GRPA2 Flexible Pipe 8,000 800mm long Polyethylene Black 5GRPA3 Reduction Adaptor 5,280 3/4 ABS Black 10G1105 Flash Vent 5,000 235 x 12 x 3,200mm EVA Black 3LMGDRR Roll-Out Ridge System 5,000 6m long - Black/Dark Brown/Terracotta 6LMGDR-T Dry Ridge Tile System 5,000 472mm long each UPVC/LDPE Slate Grey/Terracotta/ Dark Brown 10

Manthorpe Building Products LtdManthorpe HouseBrittain DriveCodnor Gate Business ParkRipley, Derbyshire DE5 3NDTel: 01773 514 200Email: sales@manthorpe.co.ukwww.manthorpe.co.ukReferences:BRE DIGEST 262/270BSI BS5250DOE Building Regs. F2NHBC Good Practice GuideNHBC Standards 7.2Manthorpe QualityManthorpe manufactures a range of ventilation andbuilding products at its headquarters in Derbyshire,under a ISO9001 Quality Assurance Scheme.All products are designed to comply with therelevant current Building Standards when fitted inaccordance with the manufacturer’s instructions.The company maintains a policy of continuousdevelopment of its product range and reserves theright to amend the specifications without notice.Issue BPublished July 2011