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    Home > Coatings News > Paints and Coatings Market > Common knowledge of coating: common mistakes of EPS board thin plastering exterior wall external insulation system

    Common knowledge of coating: common mistakes of EPS board thin plastering exterior wall external insulation system

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
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    Core tip: EPS thin plastering external wall insulation system has a history of more than ten years in China, but there are still many misunderstandings and irregularities in practical application As the saying goes, "three materials are divided into seven parts", it seems more appropriate for the external wall insulation system, which is composed of many materials, to become a final product material system after multiple construction processes on the wall With the release and implementation of the industry standard jgj144-2004 technical specification for external wall external insulation engineering, the design, construction and acceptance of the external insulation system have been improved Paint knowledge | precautions for wall paint color selection Recommended introduction: when painting the wall, the owner sometimes has difficulty in choosing what color of the wall paint to paint In fact, there is no ugly color in the wall paint, only the disharmonious color matching The use of wall color contains the knowledge of health Too strong color will stimulate people's perception, make people have a sense of fidgety, affect people's mental health Grasp the basic principles of wall color and paint a colorful space 1、 Wall paint color selection notice 1 Light color is generally used for the top surface Light colors make people feel light, dark colors make people feel heavy Usually, the treatment of rooms is from top to bottom, from shallow to deep For example, the ceiling and walls of rooms are white and Paint Home News: EPS board thin plastering external insulation system has a history of more than ten years in China, but there are still many misunderstandings and irregularities in practical application As the saying goes, "three materials are divided into seven parts", it seems more appropriate for the external wall insulation system, which is composed of many materials, to become a final product material system after multiple construction processes on the wall With the release and implementation of the industry standard jgj144-2004 technical specification for external wall external insulation engineering, there are specific specifications and guidance in the design, construction and acceptance of external insulation system This paper would like to take this opportunity to point out some common misunderstandings and irregularities in the application of EPS thin plastering external insulation system at home and abroad, and explain the consequences 1、 It is a common problem that the exterior insulation system should include the exterior decoration surface layer That is to say, the exterior insulation system is only to strengthen the glass fiber net protective layer, and the exterior decoration materials such as facing mortar and coating, tile adhesive and tile pointing agent are subject to separate bidding And most of the external insulation manufacturers do not have their own production or supporting facing materials, or even only sell one of the components of the external insulation system There are very few professional external insulation companies like sto who sell with the whole facing layer in China The consequence is that once the surface layer cracks, peeling, peeling and other quality problems occur in the future, the responsible party will not From the troubleshooting, even if it is high-quality "external insulation" (refers to only the protective layer), high-quality facing mortar or putty, if their compatibility is poor, the combination will also produce the quality problems listed above, at this time, the injured is the engineering party In recent years, with the development of the external insulation industry, most users have known that the external insulation weather resistance test is the most important test to measure the quality and service life of the external insulation system, which is regarded as the necessary and even the first condition for winning the bid, but unfortunately, it is not clear that the so-called weather resistance test must be tested with the facing layer, whether it is painted or tile facing It tests a complete external insulation system, which includes the compatibility between the facing layer and the protective layer Sto's facing mortar, even if only the quartz sand particle diameter is changed in the formula, must go through a large-scale weathering test before it can be used Facing mortar, putty, coating, tile adhesive, tile pointing agent and other external insulation supporting facing materials If the products of other manufacturers are used, the weather resistance report provided by the external insulation manufacturers is meaningless How to check the compatibility between the external insulation and the facing materials? Who will check? Who will guarantee the compatibility after the supporting use Quality? It can't be said that there will be problems in the project, but there must be risks What needs to be reminded is that a lot of external wall putty in the market at present, even if it is known as "crack resistant putty", "flexible putty", even if it can pass all indicators of the relevant national standard "flexible putty", it is not necessarily suitable for the external wall insulation system In addition, the high elastic coating with poor vapor permeability and soluble coating are not suitable for external wall insulation system The former is easy to cause wall condensation, indoor humidity and long hair blackening, and the colder the area is, the more serious the latter will corrode EPS board The ceramic tile adhesive used in the external insulation system must be a thin-layer adhesive with high polymer content The thickness of the adhesive is usually only 3-5mm It can ensure the adhesive strength and the flexibility of the external insulation It is not allowed to use the traditional thick layer adhesive, or even use pure cement mortar The jointing agent should have good cracking resistance, low shrinkage and water absorption Article 5.0.1 of jgj144 technical specification for external thermal insulation engineering of external wall stipulates that the structure and constituent materials of external thermal insulation system shall not be changed This article stipulates that the supplier of external insulation system shall be responsible for the whole set of materials finally 2、 The minimum thickness of thin plastering is specified in jgj144-2004 technical specification for external thermal insulation engineering of external wall, and the thickness of thin plastering shall be 3-6mm For cement-based systems, the thickness of thin plaster directly affects the impact resistance of the system As you know, the standard impact resistance laboratory test is based on the thickness of the protective layer of 5mm However, the impact resistance of cement-based standard mesh system with thickness less than 3mm can hardly reach 3j or even 2J as required by the standard Therefore, it is necessary to specify the minimum thickness of thin plastering The thin plastering layer of the external insulation system in Europe is divided into two layers: the protective layer and the facing mortar The total thickness is 3mm, which is not a problem In China, it is not the case, and the coating is often applied directly on the protective layer According to our observation, the thickness of the thin plastering layer of many projects is not even 2 mm, which leads to a great difference between the actual impact strength of the project and the laboratory test report The cement-based thin plastering layer with thickness less than 3mm is also disadvantageous in terms of cracking resistance and water permeability resistance, especially in the construction in high temperature season, the thickness is too small to make the water evaporate too fast, which affects the cement hydration, resulting in the phenomenon of powder and cracking 3、 It is believed that there is a consensus on the conclusion that the wool surface material with texture and texture is better than the smooth surface material in terms of cracking resistance This point is put forward here to show that anti cracking external insulation system is of great significance for such a functional product, and it is the most basic condition for external insulation system to ensure rain water penetration and long-term insulation function Therefore, it is suggested that more consideration should be given to the functionality of the external insulation system when selecting the external facing of the external insulation system Because of the hard quartz sand with larger particles, the wool surface material can also make the external insulation system obtain higher impact resistance 4、 The flatness and perpendicularity of the base surface require that the EPS thin plastering system is a paste plate process, which has certain requirements for the flatness and perpendicularity of the base surface According to the requirements of section 5.0.5 of jgj144-2004 technical specification for external thermal insulation engineering of external walls, the flatness and perpendicularity of each layer shall be ≤ 8mm / 2m; the total perpendicularity shall be ≤ 1 / 1000 and ≤ 3cm (that is, it meets the acceptance requirements for concrete or brick works) If the above requirements are not met, the base surface shall be plastered Many projects require the external insulation to correct the wall flatness and even the total height Perpendicularity Error First, it will bring the amount of glue out of control, and the cost is much higher than plastering Second, the safety of the external insulation on the wall is not good because it can not stand on the wall Based on this, at the same time, in order to save cost, many construction companies choose to use EPS boards of different thickness to adjust the wall error, which will also increase the construction difficulty, and the flatness of the board surface after pasting the board is not easy to control, which will affect the anti cracking performance of the protective layer Different slab thickness makes the insulation performance of different parts of the wall different, so it is impossible to make a reliable assessment of the energy saving of the whole building If the base surface error is too large, it is easy to cause virtual adhesion of EPS board 5、 The joint of external insulation with doors and windows, pipes and other types of work, the waterproof and crack proof closing at the details of doors and windows, balconies, wall pipes, supports and other buildings are the key points in the construction of external insulation system If not handled properly, the external insulation system often begins to crack at these details This requires that doors and windows, pipe supports and other types of work must be installed before external insulation The frequent occurrence is that the quality problems are caused in these details due to the poor connection and coordination between several types of work due to the rush of construction period This is something that the general contractor and the supervisor need to pay special attention to 6、 How to deal with EPS board joint many external insulation system projects often have cracks in the board joint, the reason is usually that the board joint is not handled properly or not at all When the EPS board is pasted, the board joint and the high-low joint are inevitable The correct treatment method is to first inject Pu styrofoam into the board joint (the wide board joint can also be filled with polystyrene board), after it is dry, cut the part protruding from the outside of the board along the insulation board surface with an art knife, and then grind off the high-low joint of the board joint with the grinding board, at the same time, polish the insulation board surface to achieve the inspection Receive the required flatness In order to avoid slab joints during construction of some projects, the edges of two adjacent heat preservation boards shall be polished into symmetrical inclined planes in advance, and V-shaped butt joint shall be formed From the outside, the workmanship is very beautiful, and there is no slab joint, but the inside is empty, which can be described as gold and jade, and the inside is covered In other projects, glue or plaster is used to fill the slab joints, and the author is surprised to see that some famous manufacturers' construction regulations for external insulation stipulate the provisions of "filling the slab joints with polymer cement mortar" In this way, the treatment of slab joint is equal to the artificial manufacturing of thermal bridge, which causes the condensation of water vapor at the slab joint, resulting in freeze-thaw damage, resulting in bulging, cracking or peeling of slab joint 7、 Whether it is necessary to add anchor bolts to high-rise buildings? Because there are a few projects in China that have had the accident of EPS board falling in large area when pasting, and the wind pressure in some areas of our country is relatively large, there is a widespread concern that the safety of additional anchor bolts is more guaranteed In fact, this is a misunderstanding The pull-out force of the anchor bolt is far less than the adhesive force of the adhesive According to the minimum adhesive tensile strength requirement of 0.1MPa of the adhesive and the minimum adhesive area of 40% of the EPS board, the adhesive force of the adhesive reaches 0.1MPa × 40% = 0.04MPa, which is equivalent to 133 anchor bolts per square meter! (according to the pull-out force of each anchor bolt is 0.3kn, 0.04 × 1000 / 0.3 = 133), the anti cracking property of the external insulation system is unfavorable, which is discussed in detail in the paper "correct use and analysis of the anchor bolt of the external insulation system of the external wall" (see new building materials 2005.5) However, the above calculation and analysis are based on the design strength of viscose In the actual construction, it is necessary to add some anchor bolts in the areas with large negative wind pressure (such as external corners, cornices, etc.) of high-rise buildings, considering that the adhesive will be affected by unpredictable strong wind if it does not reach a certain strength, and the operation of workers 8、 Detail waterproof and crack proof treatment
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