Preface:

At present, the phenomenon of "three excesses", that is, the budgetary estimate of construction projects exceeds the estimated budget, the budget exceeds the budgetary estimate, and the final accounts exceed the budget, is widespread, which seriously troubles the construction industry. As a subsidiary of the construction industry, the curtain wall industry also has this phenomenon. Nowadays, the application of various curtain walls in construction projects has become more and more extensive, and the investment amount has become larger and larger, and the curtain wall projects with tens of millions or even hundreds of millions of yuan are very common. In this case, more and more owners (builders) realize the importance of investment control of curtain wall project.

From the perspective of independence and impartiality of the third party of curtain wall consultants, the author summarizes how curtain wall consultants provide professional investment control services to owners throughout the implementation of curtain wall projects through past project experience and combined with their own professional knowledge. This kind of investment control service can help the owner to make rational use and effective control of the investment within the scope of the curtain wall project.

Investment control is the key point of curtain wall engineering project control, which runs through the whole process of curtain wall project construction. On the premise of meeting the reasonable construction period and quality of curtain wall project, it adopts the means of combining technology with economy to control investment at all stages of curtain wall engineering construction, especially at the stage of architectural design and curtain wall scheme design. The investment of the curtain wall engineering project is controlled within the limit, so that the investment of the curtain wall engineering project can play a greater economic benefit. The author believes that the investment control of curtain wall consultants for curtain wall projects should be carried out from the following aspects (key points):

Architectural design stage: provide system selection suggestions, curtain wall preliminary scheme comparison and optimization, and investment target value setting (estimation);

Curtain wall scheme design stage: design budget estimate, scheme economic optimization, economic comparison and analysis of various materials;

Curtain wall bidding stage: bill of quantities, determination of pre-tender estimate (budget), bid evaluation and bid price analysis, and assistance to the owner in signing the contract;

Curtain wall construction stage: change visa review;

Curtain wall completion stage: overall completion settlement review.

Curtain wall consultant's introduction to investment control methods and work at each stage

1. Architectural design stage

The design stage of construction project is the key stage of curtain wall investment control. After the investment decision of construction project is made, the design work is carried out immediately. The design of construction project is the process of implementing the conclusion of feasibility study and the intention of investment decision-making, the soul of project construction, and the key link of blending the relationship between construction technology and construction economy. At this stage, the plane and three-dimensional structural layout of the construction project, various construction indicators, construction technology, equipment and material standards used are determined, and the investment amount of the construction project is also generally determined.

According to the analysis of relevant data at home and abroad, in the preliminary design stage, the possibility of affecting the project investment is 75% ~ 90%; in the technical design stage, the possibility of affecting the project investment is 35% ~ 75%; in the construction drawing design stage, it is 10% ~ 35%. Obviously, the design stage of construction project is the key stage of curtain wall investment control.

In the architectural design stage, the main work of the curtain wall consultant is:

Compare and select the curtain wall scheme in the architectural design stage economically, and provide the optimized scheme;

The curtain wall scheme at this stage has been basically determined, such as whether to use glass curtain wall or aluminum curtain wall, whether to use unit curtain wall or component curtain wall. At this time, the curtain wall consultant can compare the curtain wall schemes according to the functional requirements, aesthetics, economy and other requirements of the building, select the most appropriate scheme, and provide the owner and architect with the optimized scheme for reference.

Provide economic and reasonable curtain wall system selection suggestions to architects and owners according to building data and relevant requirements;

The choice of curtain wall system also has a great impact on the cost. For the same unit curtain wall, the price of profiles and glass with different sections often varies greatly. After analysis, the author concludes that in the price composition of the unit square of curtain wall, the material cost accounts for about 80% of the unit price of curtain wall, sometimes more. In the material composition of different curtain walls, keel and surface materials account for a large proportion. The following table shows the percentage of different materials in the price of curtain wall materials:

Table 1 Percentage of different materials in the price of curtain wall materials (ordinary curtain wall)

From the above table, we can see that the choice of materials is very important to the cost of curtain wall, and the choice of keel and surface material is more important. During the architectural design stage, the curtain wall consultant will conduct a preliminary price analysis on the system materials of different curtain wall schemes, provide an analysis report, and provide suggestions on the selection of curtain wall systems to the owners and architects, so as to make the determination of curtain wall systems more reasonable and economical.

When the scheme and system are basically determined, complete the curtain wall investment estimation, that is, set the target value of curtain wall investment.

The curtain wall consultant will estimate the overall investment of the curtain wall scheme according to the requirements of the owner and the architect, and help the owner to determine the target value of curtain wall investment, which will be the control value of the overall investment of curtain wall.

Through the above work of the curtain wall consultant in the architectural design stage, the total curtain wall investment of the project can be reasonably and effectively determined in this stage, which provides a basis for the control of curtain wall investment.

2. Curtain wall deepening design stage

The detailed design of curtain wall mainly refers to the drawing design of the curtain wall scheme before bidding by the professional design unit after the determination of the curtain wall form and curtain wall system in the early stage, and the drawings used for bidding will be designed in detail. This stage is also the key stage of curtain wall investment control. At this stage, the curtain wall consultant can reasonably control the curtain wall investment from the following aspects.

Prepare the design estimate

The curtain wall consultant can prepare the curtain wall design estimate according to the design scheme. Through the design estimate, we can clearly know the preliminary cost of different types of curtain walls in the overall project. We can divide the control of the total investment of the curtain wall into each branch curtain wall, and achieve the final control of the total investment of the whole curtain wall through the investment control of each branch curtain wall. At the same time, the design scheme will be verified through the design budget estimate, and the part exceeding the budget estimate will be adjusted reasonably and effectively, so as to control the curtain wall investment within our allowable range.

Optimize the curtain wall scheme economically, adopt quota design, and control the investment expansion

Curtain wall scheme design is a process of communication and exchange of opinions. The curtain wall consultant will conduct more than one round of technical communication and exchange of views with the owner and the architect during the scheme design. In this process, the curtain wall consultant will adjust the scheme according to the opinions of all parties, and optimize the economic comparison of the adjusted scheme. Moreover, quota design will be adopted in the design to control investment expansion.

The so-called quota design is to control the preliminary design according to the approved investment estimate, and control the construction drawing design according to the approved general budget estimate of the preliminary design; we will control the design according to allocated investment quota on the premise of ensuring that the use function of each branch curtain wall is achieved; we will strictly control the unreasonable adjustment of technical design and scheme drawing design, so as to ensure that the total investment quota is not exceeded. In this way, it can be decomposed layer by layer to achieve the purpose of controlling investment and strengthening management. In order to ensure that the quota design can be carried out smoothly, at the beginning of the curtain wall project design, the owner should clarify the main indicators such as construction scale, use function and total investment quota.

Economic comparison and analysis of main curtain wall material

In the scheme design stage, the brand, specification, price and other parameters of the main materials selected for the curtain wall system will be determined. The curtain wall consultant will make further economic comparison and analysis of different brands of materials from a professional point of view based on the market performance of various materials. According to the analysis results, the final selection will be made after exchanging opinions with the owner and the architect. This can effectively avoid the price difference caused by different materials and brands.

We believe that the overall investment of the curtain wall project will be controlled within the scope of our estimation through the above work of the curtain wall consultant in the curtain wall scheme design stage. At this time, the curtain wall scheme will also be an optimized scheme combining "economy, aesthetics, functionality and safety".

3. Curtain wall bidding stage

With the increasingly fierce competition in the curtain wall market, the bidding system is further strengthened, which makes it possible to reduce the cost of curtain wall engineering and obtain greater investment returns. In order to achieve the purpose of effective control of project investment in the bidding stage, we must correctly handle the relationship between project investment and project quality and construction period, and carry out dynamic management of the whole process of project investment. In the bidding stage of curtain wall, the curtain wall consultant's control service for project investment mainly includes the following parts.

Prepare the bill of quantities according to the curtain wall bidding drawings

The curtain wall consultant can prepare the bill of quantities of divisional and subdivisional works according to the determined curtain wall bidding scheme drawings. Through the preparation of the list by the curtain wall consultant, the quantities of each sub-project can be measured more accurately, so as to avoid the difference between the bidding price and the actual price caused by the inaccuracy of the list. Accurate and comprehensive bill of quantities can also effectively avoid changes and visas in the construction process. This part of the list is provided by the curtain wall consultant to the owner for use in bidding.

Determine the base price of the curtain wall (i.e. prepare the budget) according to the curtain wall bidding drawings

The curtain wall consultant can prepare the unit square price of the curtain wall and the total cost of the project respectively according to the tender drawings and bill of quantities of the curtain wall, that is, to prepare an accurate curtain wall budget and determine the base price of the tender (this base price is only for the owner's reference). At the same time, it can also analyze the system content of different forms of curtain wall, so as to control the overall investment of curtain wall more accurately.

Conduct bid evaluation and analyze the bid price

During the bidding process, the curtain wall consultant can evaluate the bid at the request of the owner. The economic analysis and comparison shall be carried out for the bidding drawings provided by different contractors, and the detailed analysis and comparison shall be carried out for each bid price according to the prepared curtain wall budget and the material content of the curtain wall system. In this way, we can find out whether there are loopholes and ambushes in the bidding price, whether there are unreasonable low prices and high prices. The curtain wall consultant will provide the owner with a detailed economic bid evaluation report for reference when the owner determines the contractor.

Assist the owner to sign the curtain wall project contract

Nowadays, the lowest price is used to win the bid in general projects, so almost all contractors will ambush in the bidding process, leaving a foreshadowing for increasing the cost after winning the bid. In view of the above situation, the curtain wall consultant will stand in the position of the owner, check the contract signing from a professional point of view, and examine the cost of each curtain wall system, so that the contract price and the total cost of settlement of the construction enterprise are completely clear to the owner (only the design modification passed by the owner can increase the total cost). It can save the project investment for the owner and avoid the economic disputes and construction delay in the construction process.

4. Curtain wall construction stage: change visa review.

The control of project cost in the construction phase of the project is to achieve the corresponding control objectives by controlling the behavior of the contractor. The control of the contractor's main behavior is one of the most effective ways to achieve the goal of project cost control. As we all know, it is impossible to have no change in the construction process, whether it is a technical change or a price change, often the two changes are closely linked. The curtain wall consultant can control the price change by reviewing various change visas in the construction stage.

For all kinds of changes, firstly, they should be controlled in the design stage as far as possible, because the design changes in the construction process will inevitably lead to rework waste; secondly, they should be changed in advance as far as possible, the earlier the change, the smaller the loss; thirdly, before each change, we should analyze the increase and decrease of quantities and costs, and negotiate with on-site personnel to strictly control the occurrence of unreasonable changes. If the total cost of the project after the change exceeds the total budget, it must be examined and approved by the relevant departments. Many projects are not serious because of the site visa, which brings many unnecessary troubles to the project settlement and causes considerable economic losses. Therefore, strict site visa management and avoiding the occurrence of matters that cause the increase of project cost are the key to the control of project cost in the construction stage.

5. Curtain wall completion stage: review of overall settlement upon completion.

The completion settlement stage is the final stage of investment control in the whole process of curtain wall project, and it is also the last procedure. It is the main link to assess the effect of investment control in an all-round way, and it is also the mark stage for the investment results to be transferred to production or use.

The quantities of completion settlement shall be calculated according to the as-built drawings, design change orders and site visas, and the quantities shall be calculated according to the national unified calculation rules. The comprehensive unit price for settlement shall be determined according to the bidding unit price and the pricing principles and methods agreed in the contract. All charges shall be implemented in accordance with the contract agreement and the relevant policies and regulations of the local government of the project used in conjunction with the pricing quota during the construction period of the project.

At this stage, the curtain wall consultant must strictly control, carry out the settlement audit of the completed project in time according to the relevant provisions of the contract, the designated supply contract and other contracts, and make a complete settlement audit report of the curtain wall project.

To sum up, the investment control of curtain wall project is a difficult and tedious work, involving a wide range, a long period and many contents. Through the investment control service of curtain wall consultants, the investment of curtain wall projects can be effectively controlled, the phenomenon of "three excesses" can be prevented, and the investment benefits can be better brought into play. At the same time, the author suggests that the focus of investment control should be placed on the early stage of the project. Only on the basis of doing a good job in this stage, can we comprehensively and systematically implement the investment control of the whole process of the curtain wall project, and minimize or even avoid the deviation between the target value and the actual value.