attic loft conversions
attic loft conversions
 

Attic Loft Conversion Specialists

Attic Loft Conversion Specialists in North London and surrounding areas CALL: 020 8367 0066 For a FREE no obligation quote.

 
 
 
 
 
attic loft conversions

Home > TECHNICAL INFORMATION > Ventilation of rooms and roofs

Ventilation of Rooms and Roofs

Ventilation of Rooms

Habitable rooms

  • A window with an opening equivalent to 1/20th of the floor area, and
  • Background ventilation (also called trickle- or night-vents) of 8000mm², which can be closed to prevent draughts.

Bathrooms or shower rooms (with or without a WC)

  • Mechanical extract fan of 15 litres per second capacity, and
  • Either:
    • background ventilation of 4000mm², and an opening window (no minimum size), or
    • the extract fan has a 15 minutes overrun, controlled by the light switch or a humidistat.

Sanitary accomodation (i.e., a WC)

  • Either:
    • a window with an opening equivalent to 1/20th of the floor area, and background ventilation of 4000mm², or
    • mechanical extract fan of 6 litres per second capacity with a 15 minutes' overrun, controlled by the light switch or a humidistat.

If the new storey contains a kitchen or a utility room, or if there is an open-flued [i.e. not room-sealed] appliance in any room, then you should consult Building Control for further advice.

Ventilation of Roofs

The introduction of a room into a previously open roof space will restrict the flow of natural ventilation through the roof, and could cause condensation within the space between the insulation and the roof covering. The existing ventilation provision, if any, at the eaves will have to be increased, with a path for the air to flow over the insulation and out through the top of the roof slope (see diagrams 3a and 3b).

diagram 3a:

diagram 3b:

Eaves ventilation

  • A continuous 25mm wide opening or the equivalent area is required to the length of the eaves.

Cross ventilation

  • A 50mm clear air space is required between the insulation and the roofing felt.
  • The depth of the rafters may need to be increased to allow for this space plus the depth of the insulation; this can be done by adding battens to the underside of the joists.
  • If roof trimmers or hips restrict the passage of air from the eaves to the ridge, a series of 25mm holes may be drilled into these members to allow a continuous airflow. It is necessary to ensure that the location and size of these holes will not impair the strength of these members.

Ventilation at the ridge or high level

  • A continuous 5mm wide opening or the equivalent area is required to the length of the ridge.
  • Where the ceiling (or the insulation) is continued up to the ridge (as in first diagram), ventilation will have to be provided at the ridge. The ridge tiles can be replaced or altered with a vented dry-ridge.
  • If there is a flat ceiling at some distance from the underside of the ridge (as in second diagram), then the void created over this ceiling can be vented. The simplest way to achieve this is by using vent-tiles. The spacing of vent-tiles varies with each type, and the manufacturer's recommendations should be followed. The vent-tiles must ventilate the void area and not lower down the roof slope.

Vapour control layer

  • Vapour control layers can reduce the amount of moisture reaching the void and the insulation (but not eliminate it completely, hence the need for ventilation).

The walls and sloping ceiling should be lined with either:

  • a 500 gauge (150 micron) polythene sheet fixed between the lining and the insulation, or
  • a foil-backed plasterboard.

 

‘I would like to thank you for the excellent standard of service and work when completing our attic loft conversion last year.’

Laurent, Enfield

I could not be more
pleased with the way my attic loft conversion has been finished the quality of work is absolutely fantastic.’

Chris, Enfield

‘Dealing with you and your team, has been a pleasure, we are very pleased with the finished product.’

Tony, Waltham
   
approved loft_company
  
 
Website Design Services | Search Engine Optimisation Services | © 2017 Rooftop Rooms Ltd. Company no. 05014100 site map l login
 
 
 
read more about our services

London Loft Conversions Company In Enfield, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Enfield call us today.

London Loft Conversions Company In Bush Hill Park, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Bush Hill Park call us today.

London Loft Conversions Company In Barnet, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Barnet call us today.

London Loft Conversions Company In Cockfosters, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Cockfosters call us today.

Essex Loft Conversions Company In Hoddesdon, Herts Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the Essex area. For the best Loft Conversion Company in Hoddesdon call us today.

Essex Loft Conversions Company In Broxbourne, Herts Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the Essex area. For the best Loft Conversion Company in Broxbourne call us today.

London Loft Conversions Company In Islington, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Islington call us today.

London Loft Conversions Company In East Finchley, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in East Finchley call us today.

London Loft Conversions Company In Highbury, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Highbury call us today.

London Loft Conversions Company In Muswell Hill, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Muswell Hill call us today.

London Loft Conversions Company In Southgate, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Southgate call us today.

London Loft Conversions Company In Tottenham, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Tottenham call us today.

London Loft Conversions Company In Whetstone, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Whetstone call us today.

London Loft Conversions Company In Totteridge, North London Offering Attic Loft Conversions, Bungalow Loft Conversions and Dormer Loft Conversions throughout the London area. For the best Loft Conversion Company in Totteridge call us today.

EAST LONDON E1 | Whitechapel | Stepney | Mile End | E2 | Bethnal Green | Shoreditch | E3 | Bow | Bromley-by-Bow | E4 | Chingford | Highams Park | E5 | Clapton | E6 | East Ham | E7 | Forest Gate | Upton Park | E8 | Hackney | Dalston | E9 | Hackney | Homerton | E10 | Leyton | E11 | Leytonstone | E12 | Manor Park | E13 | Plaistow | E14 | Poplar | Millwall | Isle of Dogs | Docklands | E15 | Stratford | West Ham | E16 | Canning Town | North Woolwich | Docklands | E17 | Walthamstow | E18 | South Woodford

WEST CENTRAL LONDON WC1 | Bloomsbury | Gray's Inn | WC2 | Covent Garden | Holborn | Strand |

EAST CENTRAL LONDON EC1 | Clerkenwell | Finsbury | Barbican | EC2 | Moorgate | Liverpool Street | EC3 | Monument | Tower Hill | Aldgate | EC4 | Fleet Street | St. Paul's

NORTH LONDON N1 | Islington | Barnsbury | Canonbury | N2 | East Finchley | N3 | Finchley Central | N4 | Finsbury Park | Manor House | N5 | Highbury | N6 | Highgate | N7 | Holloway | N8 | Hornsey | Crouch End | N9 | Lower Edmonton | N10 | Muswell Hill | N11 | Friern Barnet | New Southgate | N12 | North Finchley | Woodside Park | N13 | Palmers Green | N14 | Southgate | N15 | Seven Sisters | N16 | Stoke Newington | Stamford Hill | N17 | Tottenham | N18 | Upper Edmonton | N19 | Archway | Tufnell Park | N20 | Whetstone | Totteridge | N21 | Winchmore Hill | N22 | Wood Green | Alexandra Palace

EN POSTCODES EN1 | Enfield | Bush Hill Park | Bulls Cross | Enfield Town | Forty Hill | EN2 | Botany Bay | Clay Hill | Crews Hill | EN3 | Enfield Highway | Enfield Lock | Enfield Wash | Ponders End | EN4 | Barnet | Hadley Wood | Cockfosters | East Barnet | New Barnet | EN5 | High Barnet | Arkley | EN6 | Potters Bar | South Mimms | Cuffley | Northaw | EN7 | Cheshunt | EN8 | Waltham Cross | EN9 | Waltham Abbey | EN10 | Broxbourne | EN11 | Hoddesdon

NORTH WEST LONDON NW1 | Regent's Park | Camden Town | NW2 | Cricklewood | Neasden | NW3 | Hampstead | Swiss Cottage | NW4 | Hendon | Brent Cross | NW5 | Kentish Town | NW6 | West Hampstead | Kilburn | Queens Park | NW7 | Mill Hill | NW8 | St John's Wood | NW9 | Kinsbury | Colindale | NW10 | Willesden | Harlesden | Kensal Green | NW11 | Golders Green | Hampstead Gdn Suburb

SOUTH EAST LONDON SE1 | Waterloo | Bermondsey | Southwark | Borough | SE2 | Abbey Wood | SE3 | Blackheath | Westcombe Park | SE4 | Brockley | Crofton Park | Honor Oak Park | SE5 | Camberwell | SE6 | Catford | Hither Green | Bellingham | SE7 | Charlton | SE8 | Deptford | SE9 | Eltham | Mottingham | SE10 | Greenwich | SE11 | Lambeth | SE12 | Lee | Grove Park | SE13 | Lewisham | Hither Green | SE14 | New Cross | New Cross Gate | SE15 | Peckham | Nunhead | SE16 | Rotherhithe | South Bermonsey | Surrey Docks | SE17 | Walworth | Elephant & Castle | SE18 | Woolwich | Plumstead | SE19 | Upper Norwood | Crystal Palace | SE20 | Penge | Anerley | SE21 | Dulwich | SE22 | East Dulwich | SE23 | Forest Hill | SE24 | Herne Hill | SE25 | South Norwood | SE26 | Sydenham | SE27 | West Norwood | Tulse Hill | SE28 | Thamesmead | SW1 | Westminster | Belgravia | Pimlico

SOUTH WEST LONDON SW2 | Brixton | Streatham Hill | SW3 | Chelsea | Brompton | SW4 | Clapham | SW5 | Earls Court | SW6 | Fulham | Parsonis Green | SW7 | South Kensington | SW8 | South Lambeth | Nine Elms | SW9 | Stockwell | Brixton | SW10 | West Brompton | Worldis End | SW11 | Battersea | Clapham Junction | SW12 | Balham | SW13 | Barnes | Castelnau | SW14 | Mortlake | East Sheen | SW15 | Putney | Roehampton | SW16 | Streatham | Norbury | SW17 | Tootings | SW18 | Wandsworth | Earlsfield | SW19 | Wimbledon | Merton | SW20 | South Wimbledon | Raynes Park

CENTRAL LONDON / WEST END W1 | Mayfair | Marylebone | Soho | W2 | Bayswater | Paddington | W3 | Acton | W4 | Chiswick | W5 | Ealing | W6 | Hammersmith | W7 | Hanwell | W8 | Kensington | W9 | Maida Vale | Warwick Avenue | W10 | Ladbroke Grove | North Kensington | W11 | Notting Hill | Holland Park | W12 | Shepherdis Bush | W13 | West Ealing | W14 | West Kensington

LONDON BOROUGHS Barking and Dagenham | Barnet | Bexley | Brent | Bromley | Camden | Croydon | Central London | Ealing | Enfield | Greenwich | Hammersmith | Fulham,Haringey | Harrow | Havering | Hillingdon | Hounslow | Islington | Kensington and Chelsea | Kingston upon Thames | Lambeth | Lewisham | Merton | Newham | Redbridge | Richmond upon Thames | Southwark | Sutton | Tower Hamlets | Waltham Forest | Wandsworth | Westminster s