QD Design is a HUB-certified architecture and MEP engineering firm in Cypress, Texas that designs churches, sanctuaries, gymnasium additions, and community buildings across the Houston metro — architectural drawings plus sealed mechanical, electrical, and plumbing engineering under one contract. Worship buildings are assembly occupancies with a unique load profile: hundreds of people for a few hours a week, then a nearly empty building. We engineer for the peak without saddling the congregation with oversized equipment running all week.
What a Church Permit Set Includes
- Architecture: A-3 assembly occupancy analysis under IBC 2021 — occupant load calculations for fixed and loose seating, egress width and exit counts, travel distances, and panic hardware coordination — plus TDLR/TAS accessibility documentation for routes, seating, and restrooms.
- Mechanical: HVAC sized for peak assembly ventilation per IMC 2021. Assembly occupant densities drive outdoor-air volumes far beyond office rates, so equipment selection and zoning determine whether Sunday morning is comfortable and Tuesday afternoon is affordable.
- Electrical: sanctuary and stage lighting, sound-system power provisions, emergency and egress lighting per NEC (2020 or 2023 by jurisdiction), service sizing with headroom for future phases, and IECC 2021 lighting compliance.
- Plumbing: restroom fixture counts per IPC 2021 driven by assembly occupant load — usually the largest plumbing scope in the building — plus kitchen or fellowship-hall service where the program includes it.
Right-Sized for Weekly-Peak Use
The most common engineering mistake in church design is treating the sanctuary like an office building: equipment sized flat for continuous occupancy. The result is a system that costs too much to buy and too much to run. On the Redeemed Christian Church facility, we designed for peak assembly loads — ventilation demand that spikes for two hours, then drops to nearly nothing — and carried the design through construction-phase change orders as the buildout evolved. On the Vietnamese Baptist Church gymnasium, we sized the main electrical service upgrade with capacity for the congregation’s future phases, so the next building project starts with headroom instead of a service replacement.
Why One A/E Firm Beats a Separate Architect and Engineer
Church projects are usually committee-led, budget-conscious, and phased over years. Every design decision — seating count, stage layout, gym addition — ripples from architecture into occupant loads, egress, ventilation, and electrical service. With separate firms, each ripple is a coordination email and a fee conversation. With QD Design, one team owns the whole set and one contract covers it, which also means one accountable party when the city’s plan reviewer sends comments. On the gymnasium project we answered the city’s electrical comments — including NEC Article 250 grounding items — through to approval ourselves.
Church Projects We’ve Completed
- Redeemed Christian Church, Houston area — full MEP design for the congregation’s worship facility: high-occupancy assembly HVAC, sanctuary lighting and sound-system power, and assembly-occupancy restroom plumbing, carried through construction-phase change orders.
- Vietnamese Baptist Church gymnasium, Houston — full-court gym addition: large-volume air distribution across the open court, main electrical service upgrade sized for future phases, and restroom plumbing for multipurpose community use. The building now serves basketball nights, youth programs, and overflow worship.
Frequently Asked Questions
How is a church’s occupant load calculated?
Under IBC 2021, assembly seating areas are calculated by seat count for fixed seating or by floor area for loose seating and standing space. That number drives everything: exit widths, restroom fixture counts, ventilation air, even parking in some jurisdictions. We calculate it early because it is the single number the rest of the design hangs on.
Will HVAC for a full sanctuary be too expensive to run?
Not if it’s designed for how churches actually operate. Assembly ventilation must meet peak demand under IMC 2021, but zoning and equipment selection can keep weekday operation modest. On the Redeemed Christian Church project we designed for the two-hour Sunday spike without oversizing equipment that would run all week.
Can you design a gym or multipurpose addition to our existing church?
Yes. Additions mean evaluating the existing building’s electrical service and mechanical systems, then extending them — or upgrading with future phases in mind. The Vietnamese Baptist Church gymnasium included a main service upgrade sized so the congregation’s next phase starts with electrical headroom already in place.
Does a volunteer-built or donated-labor project still need sealed drawings?
Yes. Assembly occupancies are life-safety buildings, and Texas cities require permitted, code-compliant construction documents regardless of who builds. Sealed MEP drawings and a proper permit also protect the congregation’s insurance position and resale value. We keep the set right-sized so compliance doesn’t mean gold-plating.
Send us your floor plan — you’ll have a fee proposal within one business day.