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foundations
Minimum of 3' 4" (1.2 Metre) below
ground level, or to below the invert
level of any adjacent drains if
greater, use 1:2:4: mix using
Sulphur Resisting Cement. All
Foundations to Local Authority
satisfaction.
Drains
New drains (where applicable) to be
flexibly jointed 4" Vitreous Clay at
minimum of 1:40 incline, and with 6"
Pea Shingle surround. Any existing
drains below new building may need
to be covered in 6" Concrete at the
discretion of the Local Authority.
Drains intersecting walls to be
protected by R/Concrete Lintols. New
Manholes if required to be of 9"
Class 'B' Brick on 6" Concrete base.
New Wastes if required to be 11/2"
(unless otherwise specified) Osma or
similar with 3" Traps. Any internal
Gullies or Manholes to be fitted
with Bolt down, Double seal,
Airtight covers.
rainwater drains
Disposal to separate surface water
drain if available on site with a
connection to the Local Authorities
approval. Disposal otherwise to be
agreed on site. Rainwater goods to
be in P.V.C. 4" Gutters 2" Pipes.
DAMP PROOF COURSES
To be approved P.V.C. type, minimum
6" above ground level and linked
into existing.
NEW WALLS
To be Bonded to existing 1/2"
Plaster and set internal finish.
FINISHED HEADROOM
Below ceiling to be minimum 7' 65/8"
(2.3 Metres). Below Beams to be
minimum 6' 65/8" (2 Metres).
VENTILATION
Minimum if 1/20 floor area to all
rooms.
STRUCTURAL STEELWORK
To be supported on 6" thick x 9" x
width of wall, P.C. Padstones and
cased in 3/4" wire bound
Plasterboard, skimmed 1/4" Gypsom
Plaster.
STRUCTURAL TIMBER
To be G.S. Grade and marked as such.
ROOF
JOISTS AND FIRST FLOOR JOISTS
To be anchored to walls at 6' 6"
centres with 11/4 x 3/16" Galvanised
Steel Straps.
CEILINGS
3/8" (10mm) Plasterboard with 3/,6"
Gypsom Skim. Polythene Vapour
Barrier with 3" Glassfibre Quilt
over. All roof voids to
be ventilated.
FASCIA BOARDS
To be 1" S/Wood or
3/4" Shiplap
impregnated with Preservative to
current building regulations.
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FLASHINGS AND
UPSTANDS
Minimum 6" high in
Zinc to all Roof Junctions and
Abutments.
SOLID WALLS
9" lightweight blocks: Celcon (0.74
'IT Value) or Durox (0.6 'IT Value)
render externally two coats
waterproof and to
BS5262/1976. 9"
Brick-work below D.P.C. level.
LINTELS
Catnic type CN7/1 for clear spans up
to 5' 10". Catnic type CN8/1 for
clear spans over 5' 10". Full Lintol
Cavity with
Glassfibre, Polythene
Sheathed. Case Lintol inside with
%" Plaster and set. 6" minimum
end bearings.
CAVITY WALLS
4%"
brickwork outside. 2" cavity with
patent butterfly ties retaining 1"
Jablite cavity liner to inner leaf.
Ties at 3'-0" staggered
horizontal centres
and 1 '-6" vertical centres. 4"
Durox aerated concrete block inner
leaf %" lightweight plaster
inside.
Combined 'U' value
0.5.11" cavity brickwork below D.P.C.,
with weepers at base. Weak mix
mortar fill up to ground level.
D.P.C. separating all
unbonded reveals and closed cavities
at plate level.
SOLID FLOORS
2" Sand and Cement Screed on 1000
gauge Polythene Membrane, linked in
to D.P.C.s on 4" Concrete over 6"
(minimum)
consolodated
Hardcore. 4" diameter Air Ducts
(with 6" Concrete below) and
Airbricks to exterior, venting
existing floor voids
if of Timber
construction.
TIMBER FLOORS
3/4"
Flooring grade T & G Chipboard on 4"
x 2" Joists at 16" centres. 3'2"
Plates bedded on D.P.C. 4^ !•£
Brick Honeycombe
Sleeper Walls at 5'0"
maximum spacings. 4" Site Concreteon
6" Consolidated Hardcore Airbricks
to external walls at 5'0"
centres. Joists to be
3/4" clear of
external walls.
FLAT ROOFS
(Cold type)
'/2" mineral chippings in
hot bitumen on 3 layers of felt to
BS 747 laid to CP 144 with hot
bitumen.
3/4"
roofing grade chipboard in firrings
or packings for (min.) 2" : 10'-0"
fall on joists at 16" Crs.
FLAT ROOFS (Warm type)
Voids unvented and
uninsulated. Walls in roof voids to
be coated with Synthaprufe. Work
generally to 'Jabdec' instructions
and N.H.B.C. Practice Note 13.
Combined 'IT value 0.35. Bitumen to
be recommended type. 1/2" mineral
chippings in hot mastic. 2 layers
felt to BS 747. Laid to CP 144 with
hot bitumen to all layers. Felt,
perforated, 1" diameter holes at 6"
Crs. laid dry 83 mm 'Jabdec' in hot
bitumen. Joints staggered and well
sealed. Bit. felt vapour barrier on
hot bitumen. 1" plywood boarding.
Firrings or packings for minimum 2"
: 10' fall on joists 6" x 2" at 16"
Crs. Plasterboard ceiling 4/8" with
3/16" Gypsom Skim.
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