Adding Space Without Starting From Scratch

Commercial building addition services in Illinois Valley and surrounding areas.

When your business outgrows its current building in Illinois Valley, an addition can provide the extra square footage you need without the cost and downtime of relocating. Turnkey Contracting by Gillan designs and builds commercial additions that integrate with your existing structure, match the architectural style, and meet all code requirements for new construction. You gain functional space that feels like part of the original building, not an afterthought tacked onto the side.

This service includes structural design, permitting, foundation work, framing, roofing, and interior buildout. The addition ties into existing systems like electrical, plumbing, and HVAC, or it may include separate systems depending on the size and use of the new space. All work follows local building codes in Spring Valley, so inspections are scheduled and passed before occupancy is granted.

If your commercial building in Illinois Valley needs more room and you want to expand on your current site, contact Turnkey Contracting by Gillan to review your options and start the design process.

How New Space Gets Attached and Made Functional

Your addition begins with a structural review of the existing building to confirm the foundation and walls can support the new construction in Spring Valley. An architect or engineer designs the addition to match roof lines, exterior finishes, and window placement so the new section looks intentional. Permitting is handled before excavation begins, and inspections are scheduled at each stage to keep the project moving forward.

When the addition is complete, you walk into a space that shares flooring, paint, and trim with the rest of the building. Doors between the old and new sections open without thresholds or level changes, and HVAC vents deliver consistent temperature throughout both areas.

The addition may require upgrading your existing HVAC system if the current capacity cannot handle the added square footage. Electrical panels may also need expansion to support new lighting, outlets, and equipment. These upgrades are identified during the design phase and included in the project scope so you are not surprised by additional costs mid-construction. Zoning regulations in Spring Valley may limit how close the addition can be to property lines, which affects the layout and footprint.

Here is what owners want to know before expanding

Clients planning an addition typically ask how long construction takes, whether they need to close during the project, and what happens if the existing building has issues that complicate the expansion.

How do you connect a new addition to an existing building without causing leaks or drafts?
The roof line is carefully flashed where the new structure meets the old, and wall joints are sealed with weather-resistant barriers before siding is applied. Interior connections are insulated and finished to match the existing space so temperature and air quality remain consistent.
Will I need to close my business while the addition is being built?
Most additions are built without requiring a full closure. Access to the existing building is maintained throughout construction, though some noise and temporary barriers are unavoidable when the two structures are connected. Final tie-ins like electrical and HVAC may require brief service interruptions scheduled outside business hours.
What site conditions limit how large an addition can be?
Zoning setbacks, easements, property line restrictions, and stormwater regulations all affect the size and placement of an addition. A site survey and zoning review are completed before design work begins to ensure the addition fits within local requirements in Spring Valley.
How long does it take to complete a commercial building addition?
A simple one-story addition can take three to six months from permitting through final inspection. Larger or multi-story additions may take eight to twelve months depending on complexity, weather, and how the new structure ties into existing systems.
What happens if the existing building has foundation or structural issues?
Those issues are identified during the structural review and must be addressed before the addition is built. Repairs are included in the project scope and budget, so the existing building is sound enough to support the new construction and remain safe for occupancy.

Turnkey Contracting by Gillan builds commercial additions across Spring Valley that expand your space without forcing you to relocate. If your business needs more room and your site allows for expansion, learn more about how we design and construct additions that match your existing building.