- Use special serrated spatula to evenly apply adhesive along the long side of the extruded plastic board to form a continuous adhesive strip with a width of about 50mm and a thickness of 8-10mm.
- The spacing of the adhesive strip should be controlled at 150-200mm to ensure that the area covered by the adhesive is ≥40% of the board area (adjusted according to the wind load requirement).
- Board fixing:
- After attaching the adhesive coated boards to the grassroots, use a level ruler to correct the flatness and check it with a 2m ruler, with an error of ≤3mm.
- Reserve 3-5mm expansion and contraction joints between the boards, and pave the boards with staggered joints (vertical staggered joints ≥200mm).
2. Applicable scenes
- It is suitable for concrete or masonry wall with base levelness ≤3mm/2m.
- In high-rise buildings, it is necessary to cooperate with mechanical anchoring (4-6 anchor bolts per square metre above 6 floors).
3. Technical Advantages
- Continuous distribution of adhesive layer, forming a uniform stress surface, shear strength up to 0.15MPa.
- Reduce the probability of hollow drum, especially suitable for areas with high wind pressure (preferred when the basic wind pressure is ≥0.5kN/m²).
Second, strip point method (Peripheral and Spot Bonding Method)
1. Construction steps
- Composite adhesive application process:
- Along the board perimeter coated 50mm wide closed glue frame, the interior according to the plum blossom-shaped layout of 100mm diameter, 10mm thick glue points, spacing ≤ 300mm.
- The total bonding area should be ≥60% (increase to 70% when wet environment or heavy finish layer).
- Secondary compaction:
- After the board on the wall need to be kneaded pressure operation (displacement amplitude of 5-10mm), to ensure that the glue point and the grass-roots level full contact.
- Focus on checking the quality of bonding at the corners, the length of edge degumming should be <50mm.
2. Applicable scenarios
- The poor flatness of the grassroots (3-5mm/2m) of the renovation project.
- Lightweight finishing systems (e.g. thin plaster) or low wind pressure areas (<0.3kN/m²).
3. Technical features
- Glue dots form an elastic stress buffer layer that can adapt to ±2mm base deformation.
- The construction efficiency is about 30% higher than that of the strip bonding method, but the denseness of the glue dots needs to be strictly controlled.
Third, the key quality control points
1. grass-roots level treatment:
- Concrete grass-roots tensile strength ≥ 0.3MPa, masonry walls need to do cement mortar levelling layer.
- Interfacer coating amount ≥ 200g/m², dry to finger touch non-stick hand before construction.
- Open time control in 1.5-2 hours, to avoid the colloid crust affect bonding.
3. Detailed treatment:
- Door and window openings with L-type whole plate cutting to reduce splicing.
- Yin and Yang corner parts staggered lap, and additional alkali-resistant mesh cloth enhancement.
Fourth, method comparison selection
Indicator
Strip sticking method
Strip point method
Bonding area
40-50%
60-70%
Applicable substrates
High levelling (Δ≤3mm/2m)
Average levelling (Δ≤5mm/2m)
Wind Pressure Resistance
Excellent (Δ1.0kPa)
Good (0.6-1.0kPa)
Material Consumption
Adhesive consumption approx
5kg/m²
6kg/m²
Construction speed
15-20m2/day
20-25m2/day
Note: According to the Technical Standard for External Thermal Insulation Engineering of External Walls (JGJ 144-2019), when the finish is facing bricks, the strip bonding method must be used with galvanised steel wire mesh and double anchoring.
V. Prevention and control of common problems
- Empty drum falling off: mostly due to adhesive open time exceeding the limit or grass-roots water content > 8%, it is recommended to use XPS boards with exhaust grooves.
- Board cracking: complete the embedded seam treatment (foaming polyethylene rod + sealant) within 24 hours after installation.
- Cold bridge effect: Anchor bolt parts need to use special heat insulation sleeve, thermal bridge loss coefficient Ψ ≤ 0.05W/(m-K).
Scientific choice of installation method and strict implementation of technology standards, can ensure that the XPS insulation system to achieve the design service life (usually not less than 25 years). It is recommended to carry out sample section test before construction to verify the bond strength and system compatibility.
