Tips for Waterproofing Your Metal Carport

If you've invested in a metal carport to safeguard your vehicle as much as possible and preserve its value, then you'll want to protect the carport, in turn. While these are well-made structures designed to last for years without much maintenance, you can nevertheless take steps to protect them from the elements. But how do you go about waterproofing a metal building like this?

Protective Barrier

Moisture is a mortal enemy of steel, and this is why you need to create a protective barrier to prevent rust. While you should always repaint the structure every few years anyway, do not use the first type of paint you come across. Instead, search for one with anticorrosion elements and think about adding a rust-inhibiting primer.

Roofing Sealant

For additional protection, use a metal roof sealant like butyl tape. It's particularly sticky and forms a good bond with adjacent pieces of metal trim. Alternatively, you can use a proprietary tube of sealant that can help to caulk the joints between pieces of metal. It will work to form a weathertight bond during any expansion or contraction cycle.

Fabric Maintenance

Get into the habit of checking the structure's fabric regularly, especially after a major storm of any kind. If it has sustained any damage from broken tree branches or other flying objects, repair it immediately. Even if the damage appears superficial, it might have broken through the protective paint layer, which could lead to rapid rusting.

Interior Moisture-Proof

As a carport is typically open to the elements on at least one side, you need to take steps to protect it from moisture on the interior. Condensation can form on the underside of the roof or the walls, especially if there is a sizeable temperature difference between day and night.

One of the least expensive forms of insulation is fiberglass. You can add this using a spray gun as it comes in liquid form and is relatively easy to get into hard-to-reach areas.


Think about using a dehumidifier to help promote good airflow within your carport. This may well be necessary in extreme cases and during the most humid or wettest months of the year.

Rust Treatment

Be on the lookout for rust at all times. You'll be surprised how quickly it can develop and take hold when conditions are perfect. If you store any items in your carport or have cupboards in a corner, look behind them from time to time. If you watch carefully and remove any corrosion before it gets a footing, this will pay dividends in the future.

Foundational Care

And don't forget the foundation. If water gets into concrete, it can eventually cause spalling, leading to cracks around the structure's base. So again, treat any anomalies when they are small and before they get the capability to enlarge.

Flooding Defense

The threat of water damage does not just come from directly above, so you should protect your carport from flooding as well. While you can never prepare for the worst type of flooding if a major waterway bursts its banks and takes over the area, you can certainly get ready for smaller events.

To begin with, clean all the guttering on an adjacent home or other buildings. Next, make sure that the downpipes are correctly directed so that they channel water to an appropriate escape route and not towards your carport. Finally, you can apply a waterproof veneer to any sidewalls, which will help to create a seal that prevents water from seeping in through any cracks.

Extra Drainage

If need be, install French drains or other solutions nearby as this will give any surface water an alternative path. If you live in a particularly vulnerable area, it may pay to install some drains within the carport itself so that if water does get in, it may have a way to get out as well.

Regular Attention

Metal carports are designed to provide maximum protection while lasting as long as possible, but you need to pay some attention to maintenance over time. First, ensure that the structure is as waterproof as possible and remains in good condition, especially after storm season has rolled around. Then, work quickly to repair any rust damage, and you can trust your carport to protect your belongings for years to come.

More Help

If you need any additional information about waterproofing a metal building, reach out to Metal Carports for advice.