Thatch Roof Chimney Height
And the thatch has either a rolled boarded or masonry gable a similar thatching method as the ridge chimney is used.
Thatch roof chimney height. Flashings and other Waterproofing for Thatch. Due to the risk of condensation forming as hot gases cool the chimney pots should be limited to a maximum height of 600mm. What is a safe chimney height above the thatch.
Flashings are waterproofing measures placed between thatch and chimneys or under windows. Flashings can be made of lead or cement fillets. The battens and laths used shall have a minimum diameter of 38x38 mm and 25mm top diameter respectively and be spaced in accordance with the requirements for the respective types of thatching material used.
But when the gable ends are turning to swing out over the wall. The chimney should be 1m higher than the thatch roof. Will last more than one ridge life.
Characteristics of thatch 61 Advantages 62 Disadvantages 7. Building Regulations Approved Document J page 32. A GUIDE TO THATCH.
18 Metres is the minimum recommended height. The thatch by raising the height of the chimney adding a chimney pot or reducing the thickness of the thatch will result in fewer active sparks reaching the thatch thereby reducing the probability of ignition. Design 101 Roof structure 102 Timber foundation supports 103 Effects of wind on thatch roofing 11.
All the turning coatwork in the gable under a chimney will lie at an angle of around 4550 degrees. Building Regulations limit the use of combustible roof coverings. Both are adequate lead lasts longer eg.
The top of the chimney or flue should be above the height of the building to prevent any wind eddies from interfering with the draw of the chimney and the evacuation of the smoke see diagram 1 and corresponding table 1. This means that below 38 degree roof pitches that the height of the flue outlet should be at least 1800mm above the roof when not close to the ridge and above 38 degree roof pitches the flue outlet height should be 2300mm horizontally back to the roof flue height figures are given in the table above where the flue is not close to the ridge. Tar and soot build-up can lead to chimney fires resulting in extreme flue gas temperatures and burning.
When the chimney sits at the apex of a gable end. A height of 45 meters is recommended as a minimum height for a chimney stack or flue although other factors need to be taken into consideration such as the roof height adjacent buildings roof windows and the material the roof is constructed from. Fire safety of thatched roofs 121 Design and construction 122.
The chimney including the pot should terminate at least 18m above the height of the ridge. Typically thatch should be at least 6 metres from the boundary for detached buildings less than 1500 cubic metres volume andor small semi-detached houses or 12m in other cases. However Approved Document B to the regulations allows Building Control Bodies to consider reduced.
Received from Building Control on Thatch and fire. Dress the area where the chimney stack penetrates the roof plane with sheet metal or fibreglass reinforced polyester flashing over and underneath the top surface as well as between the layers of the thatch. The thatcher increases the angle to 90 degrees just under the chimney.
Para 212 gives guidance on minimum chimney pot top to thatch distances. The width of the flashing should be at least 250mm. But the acceptability of this may be limited in listed buildings.
55 Chimney stacks 56 Hips 57 Valleys 58 Verges 59 Ridges 510 Use of conductors 6.
