Frequently Asked Questions

Answers to questions you may have


“Panelized Construction” means we build your walls in our shop, then ship them to your site ready to stand in place.

Our buildings start with galvanized steel framed walls, pre-fabricated in a controlled environment. Special fixtures and tooling enable us to efficiently manufacture your walls, keeping your costs down.

Our shop environment ensures consistent high quality compared to field fabrication where extremes of weather and other factors compromise quality.

Walls are manufactured with heavy gauge galvanized steel studs on two-foot centers or less, with either O.S.B. (oriented strand board) or 5/8” drywall shear diaphragms. Every piece of steel is ordered to length to eliminate waste. Special lay-up tables ensure tight dimensional tolerances.

Every sheet of O.S.B. is fastened with nearly 50 air-driven knurled pins. Collated fasteners speed the assembly process.

Firewalls are pre-assembled with one layer of drywall already installed. Additional drywall and fasteners are provided to complete these walls in the field.

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Building design is a combination of conventional framing and post and beam construction, resulting in the strongest kit-built buildings in our industry. Every engineer who has worked on our projects has told us so, and we continue to receive many compliments from building officials and contractors.

Nearly every wall is a shear wall. Roof slopes are built in eliminating the need for roof trusses. Each purlin is supported by a double-stud column built into your pre-fabricated walls. Z purlins are 6” 16-gauge or larger, not 2” or 4” as in some metal buildings. Real purlins are used at the eave, not just channels turned sideways.

Exterior walls are all double wall construction with exterior siding on the outside, an insulating air space in the stud cavity, and an inside wall cladding of O.S.B. or drywall. Mullions between doors are real steel stud walls, not just metal pans.

All structural steel is galvanized (no red iron). Walls are finished up to underside of purlins (no demo-sawn jagged edges).

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Contractors, once you have built a MODULAR building, you’ll never want to go back to the old way. Instead of arriving on a job site and spending three days sorting through 10,000 parts before you can start, you can have all the walls and roof structure assembled in place.

MODULAR buildings are easy for any good contractor to assemble. Detailed instructions lead you through the process. One or more field visits from a factory rep are included to help you get off to a good start.

End result is a first class facility with real buildings, not just glorified garden sheds.

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Customers’ things get wet in one of three ways:

  1. Condensation
  2. Leaking Roofs
  3. Damp Floors


In typical metal buildings, the steel siding you see on the outside is the same piece of metal you’re looking at on the inside. Warm moist air migrates into the building during the day, the steel conducts and radiates heat off at night, and you have condensation running down the walls and getting things wet. Some owners warn their customers not to stack things against walls.

Three ways MODULAR buildings minimize condensation are;

  • Tighter building envelope to reduce air infiltration
  • Extra insulation and double-wall construction to moderate temperature swings
  • Interior partition walls that won’t draw condensation

A tighter building envelope means less damp air getting into your buildings so there is less moisture to condense. Ceilings are insulated with 3” fiberglass instead of condensation blankets even for unheated buildings, and 6” or more in semi-heated or heated buildings. A good quality polypropylene vapor barrier reinforced with fiberglass strands (not just vinyl) helps to keep insulation dry, increasing its effectiveness.

Double-wall construction for exterior walls provides an insulating airspace that minimizes both air infiltration and temperature swings. You have siding on the outside, the airspace in the steel stud cavity, and a layer of interior cladding.

Interior walls are clad with O.S.B. (oriented strand board), the modern replacement for ½” plywood, or drywall in the case of firewalls. Moisture won’t condense on these walls like it will on steel partitions.

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Screwed down roofs have been used for years. They were the most popular type of roof for warehouses, industrial buildings, and for self-storage. Unfortunately, thousands of screws meant thousands of washers that deteriorate over time creating thousands of potential leaks. A low slope compounds this problem since water can puddle around those screws.

MODULAR’S standing seam steel roofs eliminate thousands of potential leaks. They’re installed with clips that go over raised ribs of the first roof panel and are screwed down to the building structure. The next roof panel overlaps the first with a seam that stands above the roof deck. Seams have a factory applied sealant and are often crimped in the field with a seaming tool. Screws are concealed underneath the roof deck so chances of a leak are almost nil.

Standing seam roofs are usually 24-gauge steel instead of 26, and if installed properly, will outlast screwed down roofs. MODULAR roof slopes are 1:12 or greater to ensure good drainage and look good as well. A lower slope could allow water to puddle leading to corrosion, rusting through, and roof panel failure.

At the ridge, or peak in the case of single-slope buildings, the top edge of roof panels are bent up between ribs to create a physical barrier. Special foam closures are installed between ribs to prevent wind from blowing water into building insulation. An extra wide (24”) ridge cap completes this protection.

At the eave, vapor barrier is folded back over the top of your insulation blanket. This prevents exposed fiberglass from wicking water back into the blanket. Roof panels overhang siding by 1-1/2” and are bent down to provide a drip edge. This prevents water from crawling back up under the panel and getting into your insulation.

Roof valleys are avoided. Buildings are designed so that roof junctions occur at vertical walls that are easier to flash, and much less prone to leaks.

Commercial gutters (nominally 6”) and down spouts are included to handle northwest rain storms.

Ground Level

If your site has a high water table or poor drainage, raise your foundation on 6” of crushed rock and install a 6 mil vapor barrier. Don’t skimp on fill to bring your site up to grade.

Fresh concrete contains a lot of moisture, and in our part of the country, foundations often get saturated from rain before the building goes up. On those infrequent occasions when the sun shines, open your doors and let things dry out.

One common mistake of do-it-yourselfers is pouring flat concrete floors without recessed thresholds. Water hits their roll up doors, runs down and gets blown in on the floor. MODULAR foundation designs recess the entire front of buildings with a 1:12 slope. This helps make any of your units handicap accessible.

The Ultimate Cure

Heating your building is the ultimate protection against condensation. A few degrees above dewpoint will keep water from condensing on customers’ goods.

For heated units that open to the outside, MODULAR provides insulated sectional roll up doors, not un-insulated curtain style mini storage doors

Buildings that allow daylight to stream in at the base of walls and edge of the roof, will cost more to heat. MODULAR provides insulated walls for heated buildings, even when not required by code.

Whether you fully heat and cool your buildings or just provide a minimum amount of heat to prevent freezing and condensation, MODULAR buildings save you money by keeping energy costs down. Our tighter well insulated buildings are more energy efficient.

Buildings that allow daylight to stream in at the base of walls and edge of the roof, will cost more to heat. MODULAR provides insulated walls for heated buildings, even when not required by code.

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Typical building suppliers leave firewalls up to the owner and contractor. This can be an expensive surprise.

Since our pre-fabricated walls are already framed with steel studs on 2’ centers, firewalls are NO PROBLEM.

From experience, we know where the Uniform Building Code requires firewalls, and we include them in your building package per MODULAR’s standard details. Firewalls are pre-assembled in our shop and shipped to your site with one layer of sheetrock already installed.

Your building kit will include remaining materials to complete the walls after they’re connected together and anchored to your foundation. Sheetrock over and around roll up doors is pre-cut for easy installation.

Except in special circumstances, we typically supply a one-hour firewall all the way around the perimeter of each building. This not only gives you and your customers better fire protection, but it gives you added flexibility and cost savings when it’s time to expand.

Typical building suppliers leave firewalls up to the owner and contractor. This can be an expensive surprise.

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We’ve been asked if our buildings are more expensive to insure than typical metal buildings. A major insurer of self-storage facilities, including many of our own, has told us there is no difference. Why is this so?

  1. First and most important, the largest fire-load in a self-storage building is its contents. Even though most rental contracts prohibit storing hazardous materials, what customers actually store there is a great unknown. Insurance companies assume the worst.
  2. Second, because our buildings contain some wood, I.B.C. requires our area separation walls to be placed every 9,000 Sq.Ft. Buildings that are 100% steel, have separation walls every 17,000 SqFt. If a major fire were to occur, their potential loss could be half again what ours’ would be.
  3. Third, our buildings are 90% steel anyway, and stronger than anyone else’s. If a fire starts on one side of a typical 29-gauge steel partition, heat flows immediately to whatever is on the other side and it will start burning. A hot fire will soon melt the steel partition. Steel framing on 5’ centers will lose its strength, and the building will start to come down.

With the O.S.B. partition, it will take much longer for heat to flow through the wood and ignite the contents on the other side. Even if burning, the O.S.B. will hold the wall together and maintain the building’s structural integrity for a longer time.

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MODULAR buildings are extremely tight and energy efficient.

Our steel stud walls are easy to insulate, and the entire perimeter around conditioned spaces is insulated. Insulation is fully protected on both sides of our walls by either 5/8” sheetrock or O.S.B. There aren’t any walls with easily damaged exposed vinyl blanket insulation.

Most of our insulated walls are full height to the underside of the roof diaphragm. In places where there are gaps, we provide pre-cut insulation blocks to fill any voids.

MODULAR wall junctions are tight with framed walls butting up to framed walls.

Typical metal buildings have corrugated metal butting up to corrugated metal. There is no way to easily seal these areas in old-fashioned metal buildings.

Additional insulation is provided for ceilings in climate-controlled areas (6” total).All insulation and cladding materials are included in your building package.

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Security is more important than ever. In typical metal buildings, the steel siding you see on the outside is the same metal siding you see on the inside. Pop a few screws and you’re in the next unit.

MODULAR’s superior security starts with double wall construction around the entire perimeter of each building. On the outside you have 26-gauge steel siding like many other buildings. Underneath you have a real building framed with steel studs and in inner wall of O.S.B.

Partition walls are shop assembled with steel studs on 2’ centers, minimum. Each wall is sheathed with O.S.B. on one side, with nearly 50 air-driven knurled fasteners for each 4’x 8’ sheet. They are extremely difficult to remove and provide greatly improved security over old-fashioned metal buildings. All fasteners are concealed within steel stud cavities, greatly reducing the possibility of injury or damage to peoples’ goods.

All storage units have high quality roll up doors with double latch/locks. There are NO easy to break-in swing doors.

Hallways have double walls with bright white metal siding on the corridor side, and O.S.B. on the storage unit side. Between roll up doors are real 18-gauge steel stud walls. Steel cladding wraps all the way around to the back side of the walls where it’s held in place by inaccessible fasteners.

Access to hallways is through 18-gauge steel man doors with heavy duty hinges and closers.

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