ROOFING WORK

7.    ROOFING WORK

7.1         Scope of work

furnish all labour materials and equipment for the complete installation of roofing works with insulation as indicated on the do-awing and specified herein.

7.2        Materials

7.2.1 Asphalt felt

Asphalt felt shall be asphalt saturated felt conforming to the requirement either of

1313-1  D226,  B,S  747  or  Iraqi  standard  specifications-Felt  shall  be  3Pty  Pelt consisting of  bituminous substance reinforced with fiber glass and two layers of building papers with fine aggregate,,

7.2.2 Asphalt primer

Asphalt primer shall conform to the requirements of ASM D41 of local standards specifications  using natural asphalt flux with pertroleum asphalt, and

let down with selected solvent, to produce maximum adhesion to prime suface and subsequently- applied coatings.

7.2.3. maMic waterproofing material

mastic water proofing materials shall be specific emulsion type mastic water proofing materials, such as flintkote or equivalent to be approved by the Engineer.

7.2.4 Birth filling

The materials used for roof earth fills should be free from lump, stones and of an approved  quality.  Pilling  materials  should  be  free  from  foreign  natter,  cuch  q,s nymphs of insect, rubbish  of any kind, gavel and soluble salts. Ekrth fills shall be compacted very well and shall be of 100mm average thickness to form the slopes to drain water.

7.2.5   Precast concrete tiles

The precast tiles shall be 300x800mm by 40mm thick and have a flexture strength

not less than 6001b/in , well vibrated smooth finish and shall be beded directly on the clean earth filling that is laid to slop , The joints should be thoroughly cleaned and then carefully filled with approved mastic. The mastic should be applied with headed tools and pressin, A blow luop is then run over the joint which is then smoothed with a heated jointing tool* For the skirting the size of  precast tile shall be 150x150x

000mm as aright angleshape, the vertical and horizontal joints for skirting shall be cleaned primed and filled with mastic as described above.

7.2.6 Styropor

Styropor for insulation of the roof shall have a thickness of 40mm, with thermal conductivity at 90 F° as  ( 0.2 BTu /FT-HR,F°)

7.3   Built _ up Bituminous roofing system.

7.3.1       Hoofing system shall consist of the following layers:

a.       Asphalt primer ( not less then 0.3L/m     )

b.       Asphalt ( thickness must be not less than 12mm). c.   Two layers 3Ply of asphalt felt.

d.       Insulation ( styropor)of 40 mm thickness

e.        Clean earth filling of 100mm avarge thickness

f.        Precast concrete tiles of 300 x 800 x 40mm and 20.0.x150x80Qnra for skirting with mastic jointing.

7.3.2     All surface receiving built _ up bituminous roofing must be clean free from dirt, dustf  oil grease, mortar spatter and other foreign matters and must be completely dried out before roofing is applied.

7.3.3 all sharp edge projecting from surface shall be chipped and ground smooth. All in - and - out corners and angles of deck and a butting walls or vertical surfaces shall be trowelled with cement mortar with radius of apjxreicJ 50mm.

7.3.4  fiver, asphalt primer apply auniform coating of not asphalt followed by layer of

3ply asphalt felt over entire roof and anther layer in opposite direction. Each asphalt felt shall be laid free from wirniles and buckles and lapped over proceeding layer with a minimum length of 150mm.

7.3.5     Pelt shall be applied to the vertical surface of parapet continuously from the horizontal  surface  if  practical,  or  separate  felt  shall  be  applied  over  lapping  a minimum of 2 200 mm with horizontal felt layers.