Research on the Construction Technology of Waterproofing and Anti-seepage for Green Roof

Abstract: At present, planting roofs on roofs and underground building roofs is more common in modern buildings.

The existence of this type of planting roof can increase vegetation on the roof of the building without occupying land resources, and then remove the exhaust gas and dust in the city to achieve the purpose of purifying the air and then improve the urban environment.

The planting of vegetation on the roof of the building needs to face many construction difficulties.

The most difficult problem is the problem of waterproof and anti-seepage, which should be paid high attention by engineering designers and construction personnel, and then corresponding measures should be taken to all kinds of The problem is solved efficiently, so as to show better construction quality and use effect.

Keywords: planting roof, waterproof, construction technology

1. Overall Design Analysis

The traditional design of planting roof is in the order of bottom-up:

(1) reinforced concrete roof;(2)foam concrete; (3)Mortar protection layer; (4)40 thick (SBS) modified asphalt waterproof coating;(5)40 thick root resistant SBS waterproofing membrane (copper composite tire base); (6)geotextile isolation layer;(7)fine stone concrete protection layer; (8)Composite drainage cell; (9)non-woven geotextile fabric filter layer;(10)soil layer for planting; (11)vegetation layer

2. Specific Construction Technology

2.1 Treatment of base course and construction of foaming concrete

When pouring foam concrete, it should be constructed in sections, ensuring the surface is smooth and firm, and according to the blueprint and design requirements, the foamed concrete is then scraped and scraped with aluminum alloy scraper.

After the first time, the surface is smoothed. The foaming concrete has the characteristics of large volume of foam. It can not be vibrated or pressed with a shovel to prevent foam loss. After pouring, pay attention to prevent shrinkage cracks caused by rapid drying.After curing, cover gunny bags or plastic films for moisture conservation.

2.2 Construction of mortar protective layer (leveling layer)

The mortar protective layer plays an important role in this part. Not only does it protect foam concrete, it is also the most basic part of the whole waterproof layer.

The construction quality of the mortar protective layer has an important influence on the construction quality of the waterproof membrane. It is necessary to ensure that the finished mortar layer provides a flat and solid base for the waterproof membrane.

The construction of the mortar protective layer is carried out on the slope making layer, and the mortar is in the “flow state” during the operation.

The construction is carried out according to the principle of “from far to near”. The flatness and strength of the mortar protective layer play an important role in the construction quality of the waterproof layer in the next process.

According to the setting of the separation area required by the scheme and specifications, the leveling layer in the independent separation area shall The construction joint is not allowed to be left after one-time completion.

At the same time, during the construction of the leveling layer, it is still necessary to carry out the control of slope making and line hanging.

First, it is necessary to eliminate the insufficient slope and low-lying water on the whole slope surface during the construction of the slope making layer, and it is also the basic condition to ensure that the coiled material layer and the base layer can be closely and firmly bonded;

After the water collection of the mortar, the “multiple plastering” technology is used to control the cracks, and measures such as moisture conservation are taken in time to ensure the construction quality of the mortar layer.

2.3 laying of waterproof membrane

(1)Clean the base course, ensure that the base course is dry, and also ensure that it has been accepted and qualified.

(2)The construction cold primer oil shall be stored in accordance with the instructions and specifications, and stirred evenly during use;

The method of “rolling coating” or “scraping coating” shall be adopted for painting, and the coating shall be uniform and uniform, and there shall be no bare base surface or local accumulation.

After the surface is dry, the coiled material paving construction can be carried out in the next process construction.

(3)In order to eliminate the influence of the upper structure layer on the waterproof layer and prevent the possible crack of the waterproof layer, the strip bonding method is selected.

 In order to eliminate the falling off phenomenon under the influence of the self weight of the coiled material, the full bonding method is adopted for the facade to pave and paste timely mechanical fixing measures shall be adopted;

No matter the strip bonding method or full bonding method is adopted, the joint shall be firmly bonded.

(4)Processing of edge banding

After the hot-melt method is adopted to realize the large-area coil paving construction, the hot-melt edge sealing shall be applied to ensure that the edge warping and opening will not occur;

(5)The internal and external corners appear when the roof parapet, ventilation pipe well, embedded pipe and other parts protrude from the roof plane. The internal and external corners need to be advanced, and the width of the reinforcing layer should be 500mm wide similar coiled material.

2.4 Construction of geotextile isolation layer and fine aggregate concrete protective layer

The geotextile isolation layer plays the role of isolation and good protection for the coiled material. The thickness of the protective layer is 70 mm thick concrete layer. In the process of specific construction, the following points should be highly valued:

(1)According to the actual requirements of the design, the reinforcing mesh shall be laid to ensure that the mesh is on the top of the middle, the thickness of the protective layer shall be greater than 10 mm, and each point shall be bound firmly;

(2)Some dividing joints shall be reserved. Expansion joints shall be set at the edge of some protruding roof structures and parapets. The width of the dividing joints shall be 10 mm, and then the steel bars at the dividing joints shall be disconnected;

(3)The concrete in the partition joint area shall be poured successfully in one time without retaining the construction joint. After pouring the fine aggregate concrete protective layer, the concrete shall be watered or maintained for at least one week after final setting.

2.5 laying of drainage (storage) board

The drainage and water storage sheet shall be used for laying the filter layer, and the operation shall be standardized during the construction.

The method of butt joint is used in the construction of reticulated drainage (storage) board, and the butt joint shall have neat characteristics.

When carrying out this step, we should first check and accept the base course, and then carry out the steps of empty laying and drainage (water storage) board, and then carry out the construction of butt joint. After completion, we should also check and accept specifically.

During the construction, ensure that each drainage board is in the buckled state. For the drainage (storage) board that has been laid, better protection shall be provided.

It is strictly prohibited to transport the construction materials and other items in the roof after the drainage (storage) board is laid.

Moreover, the filter layer shall be laid immediately after the drainage (storage) board is laid.

2.6 Laying of Non-woven Geotextile Filter

During the construction process of laying the non woven geotextile fabric layer, the following tools shall be used: splicing joint, surface cleaning, marking and setting out, laying polyester non-woven geotextile fabric, rolling and leveling treatment.

Among them, polyester nonwoven geotextile fabric should be laid in a relatively straight line.

In the position where the corner or bending treatment is needed, the corner or bending position of the polyester non-woven geotextile fabric shall be cut first, and then the details shall be laid with additional layers.

It is strictly prohibited to fold the geotextile non-woven fabric layer, so that the lap width of the joint of the polyester non-woven fabric in the longitudinal and transverse position is maintained at a state of 150 mm or more.

At the same time, the thread rope shall be used to sew to ensure its firmness and the upturning height shall be slightly higher than the planting soil surface

2.7 laying of planting soil layer

If the planting soil layer is laid with good natural soil, the looseness of the soil shall be ensured during the construction process, and the terrain shall be arranged according to the vertical design.

When choosing planting plants, we should select those local trees or shrubs as the most important planting objects. And the following points should be noted:

(1) Clean up the stones, construction wastes and other wastes in the planting area;

(2) According to the design requirements of the project, the soil shall be ploughed and the whole site shall be leveled to ensure that there is no low-lying water accumulation;

(3) Those positions that cannot meet the planting soil thickness should be backfilled, and the structural layer should be treated.

3.Conclusion:

In a word, in the process of waterproof construction of planting green roof of high-rise building, we should consider the factors that may affect the waterproof effect according to the characteristics of planting layer, and design a set of scientific waterproof system combined with the performance of waterproof materials.

During the whole process of project construction,reasonable organization and implementation shall be carried out, process control shall be strengthened, details shall be paid attention to, quality policy and quality objective of the company shall be oriented, and the customer’s excellent construction project shall be taken as the foothold through reasonable planning in advance, sufficient technical, material and personnel training and preparation, and under the condition that all measures are specifically implemented.

Today, with the popularization of planting roof in modern urban buildings, we need to transform the conceptual graphic design products into high-quality and reliable building physical products to create a better living environment for people.

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