through wall and underfloor ventilation

Transcription

1 through wall and underfloor ventilation

2 through wall and underfloor ventilation Sub floor and cavity wall ventilation from Manthorpe The push for thermally efficient homes has led to increasing amounts of insulation used in cavity walls and underfloor voids plus a reduction in the air permeability of the building fabric. This could increase the levels of condensation and contaminated air in these voids if not ventilated. Building Regulations Part C - Site preparation and resistance to contaminants and moisture along with the NHBC Standards Suspended ground floors outline the requirements for the type and frequency of ventilation openings to an underfloor void. The increased use of suspended floors, which are replacing the traditional methods of using concrete raft foundations in buildings has meant that the requirement to provide sufficient ventilation to the voids below floor level has also become paramount. Building Regulations and NHBC guidelines state that a gap between the ground and the underside of the floor should be provided to prevent the build up of condensation and contaminated air, and that this void should be adequately ventilated. Manthorpe s range of through wall and underfloor ventilators diffuse potentially dangerous gases, such as methane, which can seep from the ground in the space beneath timber and concrete suspended floors. They can be used individually or as a combined system to provide a complete ventilation package. Ventilators should incorporate suitable grilles which prevent the entry of vermin to the sub-floor but do not resist the air flow unduly. If floor levels need to be nearer to the ground to provide level access, then sub-floor ventilation can be provided through offset (periscope) ventilators. Two opposing external walls should have ventilation openings placed so that the ventilating air will have a free path between opposite sides. Where this is not possible, effective cross ventilation from opposite sides should be provided by a combination of openings and air ducts. As a rule of thumb, Manthorpe recommend following the NHBC guide that ventilators should be spaced at not more than 2m centres and within 450mm of each end of the opposing walls.

3 G965 dual extended underfloor vent Deeper floors, wider cavities... The current and future requirements of Part L of the Building Regulations along with other standards such as the Code for Sustainable Homes have focused on the need for well insulated homes. This has led to an increase in the depth of thermal insulation used in suspended floors along with the ever growing width of wall cavities to accommodate the greater amounts of insulation placed within them. This has meant that clear access to an underfloor void may be as far as 6 or 7 brick courses (525mm) below the level of an airbrick and potentially as much as 350mm from the outer face of the external leaf. Traditional telescopic underfloor ventilators would not be able to achieve this without the use of additional vertical and horizontal extension sleeves. The G965 Dual Extended Underfloor Ventilator is specifically designed to provide a clear airflow passage to a void beneath the insulated suspended floor construction of a modern property. The G965 ventilator offers a vertical telescopic adjustment of between 5 and 8 brick courses without the need for an extension sleeve. The horizontal outlet is also long enough to bridge through an overall wall thickness of 350mm without the need for an additional extension. This makes the product ideally suited for ventilating through a well insulated cavity wall and down below an insulated suspended floor. The front aperture of the G965 is designed to accommodate the Manthorpe G930 Airbrick but it can also be used in conjunction with a traditional clay airbrick, although using a clay airbrick could reduce the overall airflow through the system. Extensions that need to bridge a greater vertical or horizontal gap within the building construction can still be achieved by using the G961 Extension Sleeve. Similarly, details that require less than a 5 course drop in the brickwork can be achieved by trimming the required amount from the vent. Product Code Description Free Airflow Vertical Extension Horizontal Extension Material Qty G965 Dual Extended Underfloor Vent 8,000 mm 2 (7,600 mm 2 through G930) 5-8 courses (375mm - 600mm) 360mm (Including airbrick) Polypropylene 16

4 G930 airbrick G960 underfloor vent The Manthorpe G930 Combination Airbrick has been designed to provide high levels of ventilation through walls and into underfloor voids. Intended to replace a single house brick within the outer leaf wall construction the airbrick incorporates a front mounted louvred grill to permit airflow through the product but block out wind driven rain. The grill consists of evenly spaced openings specifically sized to prohibit large insects gaining access but wide enough not to be blocked by debris, paint or water droplets. A mortar key around the edge of the airbrick ensures secure adhesion to the building fabric and a clip together facility provides a choice of ventilation sizes. A single 9" x 3" Airbrick provides 7,600mm² of airflow; this can be increased by stacking more than one unit together. Multiple Airbricks can be clipped together and stacked vertically to make 9" x 6" and 9" x 9" combinations which provide 15,200mm² and 22,800mm² respectively. The G930 Combination Airbrick is available in a wide range of colours to suit many different masonry finishes and render types. Product Reference Free Airflow Size (Width x Height) G930 Airbrick 7,600 mm 2 9" x 3"/6"/9" Available in terracotta, buff, white, grey, blue/black and brown. The G960 Telescopic Underfloor Ventilator provides a clear airflow passage for underfloor ventilation to suspended concrete and timber floors. The telescopic feature enables the product to adjust the ventilation channel vertically within the cavity between three and five brick courses. The ventilator is designed to be used in conjunction with a Manthorpe G930 Airbrick at the external outlet of the product but the aperture can also accept a standard 9" x 3" clay airbrick, albeit with a reduced airflow. The G960 is narrow enough to fit within a 50mm wide cavity; this is also of benefit when fitting the vent within a wider cavity that is filled with insulation. With the use of the G961 Extension Sleeve, placed between the two halves of the Telescopic Underfloor Ventilator, the product can be extended by an additional 2 brick courses. Additional sleeves could extend the coursing drop indefinitely providing that they are adequately supported within the cavity. The G961 can also be fitted horizontally to extend the outlet through wider cavities. Product Reference Free Airflow Size (Coursing Change) G960 Underfloor Vent 6,600 mm Brick Courses Only available in black.

5 ventilation accessories weep vents and stop ends G961 Extension Sleeve G935 Cavity Sleeve cavity ventilation & drainage G950 Weep Vent G951 Peep Weep G962 Remote Void Ventilator G952 Refurbishment Weep Vent The G961 Extension Sleeve increases the adjustment of the G960 & G965 underfloor ventilators by a further two brick courses vertically. The sleeve can also be fitted to the base outlets of the vents to provide horizontal extension through larger cavities. The G935 Combination Cavity Sleeve fits into the back of a G930 9" x 3" Airbrick to ventilate through a standard cavity or solid brick wall. The unit can be stacked to create a 9" x 6" and 9" x 9" alternative, and telescopes to fit cavity widths of 50mm to 100mm, with further extension possible through the addition of extra product units. The G935 includes an integral wind baffle. The G962 Remote Void Ventilator is designed to fit the G960 & G965 underfloor vents or G930 Airbrick. The opposite end will connect to a standard 4" diameter soil pipe or can be used with a GRPA Flexible pipe. The G962 is a quick and easy way to ventilate 4" pipework that has been cast within a concrete floor. Product Reference Free Airflow Sizes G961 Extension Sleeve 7,000 mm 2 +2 Courses per unit G935 Cavity Sleeve 6,600 mm 2 9"x3"/6"/9" G962 Remote Void Ventilator 8,800 mm 2 Converts to 4" dia. Only available in black. The G950 Weep Vent is generally used to drain lintels, cavity trays and to ventilate cavity walls. The vent has a baffled grille to prevent the ingress of driving rain and wind whilst incorporating an insect grille and drip lip. The grill is specifically sized to prohibit large insects gaining access but wide enough not to be blocked by debris, paint or water droplets. The G950 Weep Vent should be simply fitted into open perp. joints and mortared in position. The G951 Peep Weep is also used to drain lintels and cavity trays without the need for ventilation. It provides a more subtle unobtrusive finish on the exterior building wall. The G952 Refurbishment Weep Vent is designed to provide cavity wall ventilation to existing walls to solve the problem of missing or inadequate ventilation. It is particularly useful in rendered wall constructions where it is notoriously difficult to use traditional built in weep vents. Product Reference Free Airflow Size (Width x Height x Depth) G950 Weep Vent 220 mm 2 9mm x 65mm x 100mm G951 Peep Weep N/A 9mm x 62mm x 115mm G952 Refurb Weep Vent 260 mm 2 25mm diameter x 80mm Available in buff, terracotta, brown, white, black, grey, clear and blue/black.

6 G900 5" core drill vent With hooded cowl G901 5" core drill vent With large backplate The G900 5" Core Drill Vent is designed for use when ventilating a gas appliance or supplying general through wall ventilation. Using a standard 5" core drill, the system can be fitted quickly and easily in both new build and refurbishment situations. The system has been designed to provide the maximum free area with the minimum visual impact. The cowl and louvre vents significantly reduce any visible light and gusty winds as well as blocking wind driven rain and large insects. The duct creates an uninterrupted path through an exterior wall up to a maximum thickness of 350mm. An optional anti-draught baffle can be used whenever the ventilation requirements allow a reduction in airflow. Without the anti-draught baffle installed, the product s measured free area is 10,000 mm² which is enough to provide ventilation to a 27kW or 92,000 Btu/h appliance. With the anti-draught baffle, the effective free area (as tested by the BRE) is 7,000 mm², enough to provide ventilation to a 21kW or 71,500 Btu/h appliance (airflows in accordance with BS 5440 Pt.2:2000). Product Reference Free Airflow Size G900 5" Core Vent 10,000 mm 2 without baffle 7,000 mm 2 with baffle Max. 350mm long, 125mm diameter Available in brown, terracotta and white (Internal louvre grill always white). The G901 Large Backplate 5" Core Drill Vent is similar to the G900; however it has the addition of a larger perimeter backplate. The backplate gives the installer greater flexibility, allowing them to simply cut masonry away with a hammer and chisel to fit the product and cover any inaccuracies afterwards. It will also cover any damage that may have occurred as a result of using a core drill. This is especially useful in a refurbishment situation when all of the decorating inside the property has been completed. BEFORE Product Reference Free Airflow Size G901 Large Backplate 5" Core Vent 10,000 mm 2 without baffle 7,000 mm 2 with baffle AFTER 275mm Max. 350mm long, 125mm diameter Available in brown, terracotta and white (Internal louvre grill always white). 207mm

7 Manthorpe Building Products Ltd Manthorpe House Brittain Drive Codnor Gate Business Park Ripley, Derbyshire DE5 3ND Tel: References: B.S :2009 Part 2: Specification for installation and maintenance of ventilation for gas appliances. B.S 5250: 2011 Control of condensation in buildings. Building Regulations Part C - Site preparation and resistance to contaminants and moisture. NHBC Standards 5.2: Suspended ground floors. NHBC Thermal Insulation and Ventilation - Good Practice Guide. Manthorpe Quality Manthorpe manufactures a range of ventilation and building products at its headquarters in Derbyshire, under a ISO9001 Quality Assurance Scheme. All products are designed to comply with the relevant current Building Standards when fitted in accordance with the manufacturer s instructions. The company maintains a policy of continuous development of its product range and reserves the right to amend the specifications without notice. Issue B Published June 2013