Drive Projects Offsite with Accurate Prefab Planning, Forecasting and Estimation

Many builders and contractors are actively investing in offsite construction by launching new self-perform prefab businesses and factories. While this is great news for the construction industry at large, it is crucial that technology and processes are implemented in parallel with these investments to ensure these new prefab businesses and operations are successful.

Builders and contractors need a better understanding of which parts of a large scale project are best suited to be prefabricated and how they need to manage their labor, materials and logistics to achieve the major cost, speed and delivery advantages that come with building offsite. 

In this edition of the How To Guide for Prefab Leaders, we review how Offsight's Forecasting & Estimating feature set can be a gamechanger when it comes to accurately estimating prefab costs and forecasting your prefab project schedule. This tool is built to help with planning and bidding on major offsite projects and can help drive projects to your prefab factory. 

Planning and Forecasting Your Prefab Schedule

In order to correctly plan and forecast your prefab project schedule, it’s crucial that you understand how labor constraints and capacity specifically tailored to a factory production environment can impact your project delivery speed and cost. With Offsight’s Forecasting & Estimating functionality, you can define your prefab production with target workflow process times for each stage in the prefab process.

This is the first step in building your forecast and schedule. In this guide, we will walk through an example of a prefab factory that specializes in manufacturing wall panels. With Offsight’s pre-built prefab planning, forecasting and estimating templates, prefab managers can model entire workflows based on previous projects with existing labor and production constraints to streamline setup.

To build your plan you need to begin by defining the physical stages or work areas in your prefabrication process. These can include Framing, Subassembly, Sheathing, Insulation, etc. After defining the stages in your prefab process, it's important to assign labor requirements and resources to your process. Labor will be the primary constraint in gauging the speed and cost of completing your project.

Through Offsight’s Planning Dashboard, labor can be assigned with a rate per hour based on their role and skill set and a start date to specify when they should start working on the panelized project at the prefab factory. Factory working hours and target labor hours define how long it would take to complete a process e.g. Sheathing for a specific type of panel and the total process time would forecast the timeframe to complete a product. 

In order to make our plan even more accurate, it’s important to specify all types of panel designs e.g. Interior, Exterior, Load Bearing, etc. that would be part of this project including how each design would move through the prefab process and approximately how many labor hours would be needed to complete each step in the prefab process. To receive an accurate production forecast, it’s important to also identify each panel as a product e.g. Panel - A1 and link this with that panel’s specific design we identified earlier. Finally, we set the sequence in which the individual panels proceed through the prefab factory during production. This sequence may be related to the order in which each floor on the job site may be constructed e.g. all panels on the 1st Floor start before all panels on the 2nd Floor and so forth. 

Now that our plan is set, we can leverage Offsight to automatically generate a detailed production forecast and prefab schedule. We can easily review when each panel would be forecasted to start and complete based on our labor constraints and visualize the entire project plan in Offsight’s dynamic GANTT Chart. If the owner or developer needs to accelerate project delivery, the prefab factory can modify labor resources by either adding more personnel or reducing the time between start dates to accelerate. We now have a highly dynamic prefab plan and labor cost estimate for our project which we can reference in our bid package. 

Performing Materials Takeoff and Costing

After modeling our labor costs, the next part is calculating material costs with Offsight’s Takeoff tool for your prefab project. The materials costs can be added to our project by linking a Bill of Materials (BOM) with each unique panel design. You will recall we defined these earlier based on the type of panel. In some cases BOMs may be unique per Product e.g, Panel - A1  has a unique set of materials that are significantly different than Panel - A2. In either case the unique BOMs can be linked through Offsight’s Takeoff Dashboard. 

Once the BOMs are linked to their appropriate designs with materials and costs per unit identified, we can then link costs across all products we identified earlier in our plan to arrive at the total material cost for our prefab project. 

Finalizing Your Prefab Estimate

With the addition of material costs, we now have a highly accurate picture of what our prefab project would cost. As a next step, we need to access Offsight’s Estimation Dashboard to complete our costing.

With Offsight’s Estimation Dashboard feature set, we can automatically pull a plan and all associated labor costs including factory prefabrication and installation costs and pair this with the appropriate materials costs for that plan. We can then add in logistics costs which can include shipping, warehousing and delivery. These costs can be entered as a fixed cost per a vendor’s quote or as an overall percent of project costs to account for variability in price that can scale with a project's complexity. 

Once these final elements are added, Offsight’s Estimation Dashboard will provide a complete project cost breakdown for your prefab project along with a full project schedule and forecast. These documents can be included in active bids or for better internal or external alignment with project stakeholders. Furthermore, this will provide your prefab team with the tools needed to accurately bid on projects and advocate for prefabrication to meet the project objectives and goals.