About ExteriorCalc
ExteriorCalc is an independent construction calculation and material takeoff platform built specifically for residential siding, rainwater drainage, and roof edge ventilation planning.
Team & Authorship
Alish Gautam
Developer of ExteriorCalc
Alish Gautam is the creator and developer of ExteriorCalc. He is responsible for website architecture, algorithm design, user interface engineering, and implementing deterministic calculation engines.
He translates geometric formulas, trade installation guidelines, and architectural takeoff practices into accessible computational tools for estimators, contractors, and homeowners.
- •Software engineering and interactive calculation logic
- •Mathematical modeling of construction geometry and material takeoffs
- •Site architecture, performance, and accessibility
Bijay Katwal
ReviewerCivil Engineer
Bijay Katwal is a Civil Engineer who serves as the technical reviewer for ExteriorCalc.
He reviews the mathematical models, formulas, and technical reference tables used throughout the platform to ensure their theoretical soundness and consistency with published standards, such as the International Residential Code (IRC) and SMACNA guidelines.
- •Technical review of engineering equations and geometric models
- •Verification of formula alignment with building codes (IRC) and trade standards (SMACNA, VSI)
- •Review of calculation assumptions, conversion factors, and drainage formulas
How Calculations Are Developed & Reviewed
ExteriorCalc relies on an open, transparent development and verification workflow to ensure calculation models remain accurate, reproducible, and aligned with standard trade practices:
Formulas and variables are sourced directly from established documents, including the International Residential Code (IRC Sections R806, R703, R903), the SMACNA Architectural Sheet Metal Manual, and manufacturer technical specifications.
Alish Gautam translates geometric equations and material packaging constraints into deterministic TypeScript calculation engines executing at full 64-bit IEEE 754 precision.
Bijay Katwal, Civil Engineer, reviews the mathematical logic, conversion factors, fluid catchment equations, and ventilation balance principles for technical integrity.
Formulas, variable definitions, worked examples, and underlying assumptions are openly published alongside each tool rather than hidden behind closed algorithms.
Scope & Professional Verification Notice
ExteriorCalc is designed to assist estimators, builders, and homeowners with preliminary planning and material budgeting.
Technical review by our Civil Engineer reviewer focuses on the general mathematical logic and standard model representations. Because local building codes, framing tolerances, microclimates, and manufacturer warranty conditions vary by jurisdiction, ExteriorCalc calculations do not replace professional on-site engineering, architectural services, or municipal code inspection. Always verify critical dimensions and plans with a licensed local contractor or building official.