Can You Roof Over Architectural Shingles?

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

Architectural shingles are growing in popularity each year. They give roofs a contemporary aesthetic appeal with their flat roof surface and appealing finish. However, because of their unique design, many people are unsure whether they should reroof them.

You can roof over architectural shingles, provided your roof has the necessary support structures in place. However, roofing over architectural shingles may not be an intelligent move, and it’s certainly not as straightforward as roofing over traditional 3 step shingles.

Keep reading for more details about roofing over architectural shingles. We’ll explore the benefits and drawbacks of this practice, as well as whether you can roof over 3 step shingles.

Should You Roof Over Architectural Shingles?

You’re likely already aware that it’s possible to roof over architectural shingles. The real question is whether it’s a wise move in a financial and practical sense. So, should you go ahead and roof over architectural shingles, or are you better off removing the old shingles before adding new ones?

You shouldn’t roof over existing architectural shingles. The main reason is that it will be nearly impossible to flatten down the new layer of shingles completely. This can allow winds and storms to lift the new shingles, causing damages to your roof.

Roofing over architectural shingles is likely to create more issues than it’s worth. In fact, many architectural shingle manufacturers advocate that you avoid roofing over existing shingles.

The majority of roofing companies will also reject the idea. It’s unlikely to be functional and aesthetically appealing, which is the whole point of paying extra for architectural shingles in the first place.

With so many potential risks arising from reroofing over architectural shingles, it’s simply not worth the hassle. This is especially true if you’re attempting to add new architectural shingles over existing ones.

If your old architectural shingles are due an upgrade or have been damaged, you should hire competent roofers to remove the existing shingles and replace them with new ones. Hiring experts to lay more shingles over existing shingles is likely to cause further issues for your roof.

What Are the Risks of Roofing Over Architectural Shingles?

Roofing over architectural shingles can be a messy affair. The nature of architectural shingles and installation can create many problems and potential issues when adding more shingles over the existing layer. So, what are the risks of this procedure?

Here are some of the risks of roofing over architectural shingles:

Adds weight
Makes the roof more prone to wind and storm damages
Makes existing issues worse
Creates heating and cooling issues

Read below for a breakdown of the risks involved in roofing over architectural shingles.

Added Weight

Architectural shingles weigh considerably more than traditional 3 step shingles. The roof support structure is already supporting the extra weight added by architectural shingles, and it was probably not designed to have another layer on top of it. Adding an extra layer of architectural shingles over the existing one will likely be too much weight for most roofs to support.

When your roof is supporting more weight than it was designed for, issues are likely to start appearing. The shingles may start letting leeks or rain pass through. On top of this, excessive weight significantly increases the risk of your roof collapsing.

Wind and Storm Damages

Architectural shingles form a smooth and sleek surface on your roof. These shingles are laid in a specific way that provides them with added protection and resistance to wind and storm damages.

However, when you add a new layer on top of the existing shingles, they’ll likely not be completely even.

If your architectural shingles aren’t entirely flat, they can catch strong gusts of winds. A strong draft could cause them to crack or split. All in all, your roof will be significantly more vulnerable to storm damage when there’s more than one layer of architectural shingles on your roof.

Makes Issues Worse

Architectural shingles are more durable and resilient than traditional shingles. Therefore, when your architectural shingles have an issue, it’s likely an indication that there are other, larger issues within the structure of your roof.

If you add a layer of architectural shingles over the existing later, you won’t be resolving the underlying issue that’s damaging your roof. The added weight of the new layer of shingles will only make such matters much worse, resulting in the need for additional repairs.

Heating and Cooling Issues

One of the most important aspects of any roof is its insulation qualities. Many people overlook this aspect and don’t realize the impact that a roof can have on your heating and cooling expenses.

A well-kept and adequately installed roof with architectural shingles will keep the outside air out of your home, reducing the energy needed to heat and cool your home.

However, a roof with more than one layer of architectural shingles will likely have imperfections or gaps in the design. As we explained before, adding a layer on top of the other will result in the new being applied unevenly and leaving gaps.

This allows air to freely pass through, which massively hurts your property’s energy efficiency. When your energy efficiency goes down, your home will require more power to run. More energy inevitably results in higher energy bills, which can quickly add up to a lot of additional expenses.

These expenses can build up to be even larger than the cost of removing the old architectural shingles before applying new ones. Roofing over architectural shingles is simply not financially sound.

Final Thoughts

Architectural shingles are the premium option when it comes to adding shingles to your roof. Modern architectural shingles are robust, durable, and highly effective. Architectural shingles are also very aesthetically pleasing.

You technically can install architectural shingles over existing architectural shingles. However, this can pose several risks to your roof, including adding too much weight to its supports.

It’s best to avoid adding additional layers of architectural shingles. Instead, you should hire experts to rip off and replace any damaged shingles on your roof.