Yeoman YMMB manual Flue Outlet Positions, Minimum dimensions Hearth, For advice before proceeding

SITE REQUIREMENTS

2. FLUE OUTLET POSITIONS

These positions are defined by Document J of the Building Regulations.

IMPORTANT: Seek specialist advice if installing in a dwelling with a thatched roof

Adjacent Building

Terminal

Flue

Vertical

Measurement

Horizontal

Measurement

150mm

max

Adjacent

Building

Insulation

		The datum for vertical measurement is the point of
		discharge of the flue from either the point of discharge
		of the flue or 150mm above insulation, whichever is
		the lower.
	Point where the flue passes through weather surface	Clearances to flue outlet
	(Notes 1 &2)
A	At or within 600mm of the ridge	At least 600mm above ridge
B	Elsewhere on roof (whether pitched or flat)	At least 2300mm horizontally from the nearest point on the weather surface and:
		a) at least 1000mm above highest point of intersection of the chimney with and
		the weather surface; or
		b) at least as high as the ridge
C	Below (on a pitched roof) or within 2300mm horizontally to	At least 1000mm above the top of opening
	openable rooflight, dormer window, or other opening (Note 3)
D	Within 2300mm of an adjoining or adjacent building, whether or	At least 600mm above any part of the adjacent of building within 2300mm
	not beyond the boundary (Note 3)

Notes:

1) The weather surface is the building external surface, such as it's roof tiles or external walls.

2) A flat roof has a pitch less than 10°.

3) The clearance given for A or B, as appropriate, will also apply.

4) A vertical flue fixed to an outside wall should be treated as equivalent to an inside flue emerging at the nearest edge of the roof.

3. Minimum dimensions - HEARTH

150

500 225

Superimposed Hearth (or area to be free of combustible material)

150Constructional

Hearth

3.2	If this appliance can be installed in an elevated setting it
	is recommended to increase the 225mm hearth depth to
	safely contain any falling logs or embers. The higher the
	appliance is installed the deeper the hearth should be to
	avoid scorched floor coverings.
3.3	The building must have a suitable load-bearing capacity for
	the hearth and appliance. Consult a structural engineer
	for advice before proceeding.
3.4	When fitting into an existing hearth check that the hearth
	complies with current construction regulations and is at least
	the minimum sizes shown.

789

3.1The appliance must stand on a non-combustible constructional hearth which is at least 125mm thick with the minimum dimensions as shown in diagram.

3.5 If there is no existing fireplace or chimney it is possible to

construct a suitable non-combustible housing and hearth

setting. The flue must be installed in accordance with all

local and national regulations and current rules in force.

Check if adding a new chimney to your property requires

planning permission.

15