Construction technology of roofing screed

1 scope

This technology is applicable for industrial and civil construction to pave and stick roll roofing construction of grass-roots screed.

2 construction preparation

2.1 materials and requirements:

2.1.1 quality and technical properties of the materials used must comply with the design requirements and specification for construction and acceptance of rules.

2.1.2 cement mortar:

2.1.2.1 cement: no less than No. 325 of ordinary Portland cement.

2.1.2.2 sand: suitable for sand, clay is less than 3%, does not contain organic impurities in order to better.

2.1.3 asphalt mortar:

2.1.3.1 asphalt, 60th, 60th ordinary asphalt, asphalt or 75th.

2.1.3.2 sand: sand, clay is less than 3%, does not contain organic impurities.

2.1.3.3 powder: can use slag, shale powder, talcum powder, etc.

2.2 the main tools:

2.2.1 mechanical: concrete or mortar mixer blender.

2.2.2 tool: transportation trolley, shovel, trowel, level of iron shaving staves, level, pitch pans, Fry Pans, pressure rolls, soldering iron.

2.3 operating conditions:

2.3.1 screed before the roof insulation layer should check acceptance, and the acceptance formalities.

2.3.2 various embedded pipe through the roof, chimneys, parapets, warm roots of trench walls, expansion joints should be according to the design and construction drawings and specifications to deal with.

2.3.3 according to the design requirements of the elevation, slope, and find the rules and play the line (including the slope of the gutter and gutters).

2.3.4 construction when the screed the surface should be cleaned, processed and combination of grass-roots and screeds, such as watering moist, asphalt spraying thinner.

3 operational processes

3.1 process:

Grass-roots cleanup → gradient tube sealing → elevation line → sprinkler wet →

Construction leveling layer (cement mortar and mastic asphalt screed) → maintenance → acceptance

3.2 grass-roots cleanup: the configuration layer, insulating layer on the surface of clean loose debris, ash slag bonding of the convex surface of grass-roots stuff to bulldoze and shall not affect the effective thickness of the screed.

3.3 pipe plug: large area before doing the screed, roofing should be first the onion, movement joints, roof heating Groove wall handle it.

3.4 the cement mortar screed:

3.4.1 water wet: wipe before leveling layer of cement mortar should be proper sprinkler wet surface of the grass-roots, which is a combination of primary and screeds against, but not watering too much, so as not to affect the drying of screed surfaces, nest after waterproof layer construction moisture, waterproof layer hollowing. So the sprinkler reaches the grass-roots level and screed solid combination.

3.4.2 posted elevation, Chong tendons: according to the slope requirements, drawing glass, generally by l~2m posted point elevation (with grey bread), when Pu leveling mortar, flow direction spacing l~2m bar, and set the screed joints, width is generally 20mm, and will be communicated with the insulation seam, sew a maximum spacing of 6m.

3.4.3 paving cement mortar: Press Pack ash, paving, scrape shoulder washed ribs scrape, use wood trowel after Cha-iron trowel. Beach ball sinks after loss, people stepped into the footprints but not to cave in to, then with an iron trowel pressure a second time to let's give. Leveling layer of cement mortar mix 1:3, mix consistency control in 7cm.

3.4.4 maintenance: after a screed trowel, compacting 24h water conservation, curing period of 7d, after the drying laying the waterproof layer.

3.5 asphalt mortar screed:

3.5.1 oil spray cooling Base: grassroots clean, spray two or even cold oil, as a combination of asphalt mortar screed layer.

3.5.2 preparation of asphalt: asphalt melting and dehydrating before preheating to 140℃; sand and powder mixing evenly, add preheat the melting asphalt mixing and further heated to requested temperature, but should not result in overheating, prevent asphalt deterioration Carbide. Temperature of asphalt mortar construction requirements are shown in table 10-2.

Asphalt temperature requirement for the construction of table 10-2

Asphalt temperature outdoor temperature (℃)

(C) finished mixing start rolling rolling

140~170 90~100 + 5 degrees centigrade above 60

+ 5 c ~-10 c 160~180 110~130 40

3.5.3 asphalt paving:

3.5.3.1 spread, find slope leveling cakes, space 1~1.5M;

3.5.3.2 asphalt laying the screed, slope line cable shop cake, paving asphalt, with long scrape scraper, water roller rolling, at the corner of available iron iron, compacted to achieve surface smooth, dense, non-cellular, see indentation as well.

4 quality criteria

4.1 project:

4.1.1 raw material and mixture ratio, must comply with the design requirements and specification for construction and acceptance of rules.

4.1.2 roofing, gutter, gutter slope leveling layer, you must comply with the design requirements, roof slope of not less than 3%; gutter, gutter longitudinal slope of not less than 5 per thousand;

4.1.3 cement and asphalt factory certificate, or test data.

4.2 Basic project:

4.2.1 No peeling, sand cement mortar screeds and other defects.

4.2.2 homogeneity of asphalt mortar mixes, asphalt screed should be covered by dense, no cellular and other defects.

4.2.3 screed and highlight the junction of roof structure and the corner should be rounded or obtuse angle, and require neat and smooth.

4.2.4 screed joints design placement and spacing, should comply with the design and specification for construction and acceptance of rules.

4.3 allowable deviation, as shown in table 10-3.

Roof screeds tolerance table 10-3

Project tolerance (mm) method

1 surface 5 2m m on foot and wedged feeler Gage check

5 finished product protection

5.1 good screed on, push trolley transportation, you should shop scaffold lane in order to prevent damage to surface of the screed.

5.2 screed after construction, reaches a certain intensity shall not be trampled by people at the end.

5.3 gullies, the inner row of rain during construction, sealed for interim measures should be taken to prevent debris into the Tasse.

6 quality problems to be noticed

6.1 leveling sand: cement mortar screed construction maintenance not so that screed of early dehydration; too much mortar mix with water, affecting the product strength; wrong time later destroys the cement hardening Stampede prematurely destroy the surface hardness of health. Construction in the mix, controlling the amount of water, mastering pressure time product people too soon.

6.2 screed hollowing and cracking: the primary surface is not clean, not wet with water well before the leveling layer of cement mortar construction, resulting in empty drums; pay attention to grass-roots cleanup, serious construction bonding process, pay attention to compaction. Because cement mortar with sand fine, graded well, leveling uneven, inadequate maintenance, can create screed cracking; note that complies with the requirements of abrasive, evenness of insulation layer should be strictly controlled, guarantees consistent screed thickness, strengthening product conservation, prevent surface cracking.

6.3 the pan of water: heat insulation construction shall be guaranteed to find a pan of water, insulation layer of screed should be checked before the slope flashing whether it meets the requirements, laid screeds should have a slope and thickness.

7 quality records

This standard shall meet the following quality records:

7.1 material and test information.

7.2 quality inspection and assessment of information.