In just a few easy steps
Many roofers have some idea of what can be achieved with AppliCad Roof Wizard, but don’t really understand how it works. We thought that a brief overview might help you understand how we model and estimate a roof from aerial images. We have listed some basic steps below so you can better understand how we go about estimating materials and producing a detailed report.
The key motivator here is to understand how AppliCad’s competitors charge you for a similar service, and compare how you can then manage the reports for yourself and check that they are correct, thus improving your accuracy and efficiency. Don’t wait days for a result, do it right when you need it with Roof Wizard. From start to finish, it might take you 20 minutes, and you’re done.
Step 1. Scope Job and Determine Key Factors
We spent roughly 5 minutes going through the images for the job, looking at it from various angles and determining pitch or roof slope. This is one of the trickier parts of estimating from an image as they can often be deceiving. The images at the top of this email show some of the tools in the software we used to determine the pitch. Imagery here taken from Google Street View (note – this isn’t always available and if not, you might use Bing Bird’s Eye view to help you).
You may also use images that you have captured yourself using a drone mounted camera – but make sure that you are aware of the limitations of using a drone caused by parallax error or image distrortion due to your altitude being too low or at an oblique view of the structure.
From our measurements, we can conclude that we have about an 8/12 pitch. If you’re not totally confident, then you could simply use a greater pitch value. We would rather be a little over than a lot under.
Step 2. Get an Overall Scale
Again, here you would extract an accurate measurement using the Google Earth measure tool, once you confirm which address it actually is! We know this sounds ridiculous, but when we first typed the address into Google Earth, and cross checked it with Bing Maps, there was a disagreement as to the correct location. Here we have measured the eave length from Google Earth, and have the back eave line at roughly 41’6″ long. Again, you might overestimate this if you want to cover all your bases, but that adjustment is usually not necessary. The software has waste calculations built in:
Step 3. Draw Second Storey Roof (getting soffit overhangs right)
To do this, we bring the underlay image into AppliCad, scale it to the right size and then simply digitize an outline of the roof. You are now working at full size!
The software then asks for the walls to be moved in (because we specified a negative soffit overhang) and the roof is drawn automatically in 3D using the pitch value, the eave height and overhang we specified:
We modify the soffit overhang at the gable (front) because it looks like about 12″ instead of the 18″ we used for the remainder of the upper roof. This was a simple stretch routine. Note, this only becomes important when cutting out the lower roof.
Step 4. Draw the Lower Roof
You then do the same for the lower roof, knowing that we won’t be using all of it because some of it gets cut away by the upper roof wall line:
Step 5. Cut away Upper Wall Line from Lower Roof
This is a simple routine that auto-tracks around the upper roof line and subtracts the redundant area from the lower roof.
Step 6. Tidy Up
We then used manual digitizing from the same routine in the last step to remove some other parts of the roof. In addition to this, we trimmed the upper roof section down to the lower roof, as outlined in the birds-eye views, where it can be clearly seen that the upper roof rakes down over the front entryway. Some of the edits include adding in the little “jut-out” on the upper storey (left side), deleting wall lines and removing the underlay image.
Step 7. Estimate the Job
With the job drawn up and scaled correctly, the Shingles can be applied (we specified a Certainteed Patriot Shingle) and calculated. We use our ‘coursing method’ to do so, which applies all shingles to the roof, course by course, and counts how many there are very precisely. Waste factors that you define for your needs are automatically applied to ensure that you order the correct quantity.
You might also apply other materials from he material database, such as metal, tile or slate. With metal you may use metal tile (estimated the same way as shingle – course by course) or metal as standing seam or formed panel (estimated panel by panel based on the cover width).
Step 8. Print the Report
We then produced a report of this estimate from the ‘Job Costing’ screen. See attached. This could also include all installer’s labor and overhead costs.
Click here for a sample report for this job – design your own template or use one of our predesigned templates.
We hope that this gives you an idea of what we do and how you could do it for yourself too.
Estimating/Take-off Bureau Service
Alternately, we could model the jobs for you and return report estimates, based on you providing us with basic information about how you estimate. There is a one time setup cost in this, but once we have your information, we can then produce estimates like this for you from then on. We provide this through our service bureau – click here to review the service.