How To Repair Shiplap Roofing

You’ve decided to replace your roof. Following a few estimates, several roofing companies suggest tearing up your old roofing material and replacing it with plywood.

If you’re wondering why your roofers can’t simply install new shingles and roofing accessories on top of your old roof deck, one of the most prevalent reasons is that your roof deck is shiplap. When plywood hadn’t yet found its way into a new building in the 1950s and 1980s, shiplap roof decking was extensively employed.

Shiplap resides beneath the roofs of many homes over thirty years old, having been designed specifically for asphalt shingles in the early days of its manufacture. Shiplap is currently seen as a competitor to asphalt shingles. Most shingle manufacturers won’t warranty a roof that sits directly on shiplap.

Why Do You Need To Repair Or Replace The Shiplap Roofing?

One of the main reasons it’s difficult to place shingles directly over this subpar roof decking is that shiplap moves and shifts.

All shiplap expands and contracts during the winter and summer seasons, some more than others, and as a result, the shingles tend to move when they are not supposed to move. This, in turn, can cause roofing nails or staples to back out of the roof deck over time.

We’ve seen roofing nails explode right through the surface of asphalt shingles in some cases, and entire roof decks in others, creating a slew of leaks and other water-related damage. Shiplap fir wood resin disappears over time, causing the boards to shrink, split, develop knot holes, and become highly brittle.

Between the once-tightly-fitted shiplap planks, open spaces appear. If the roofing underlayment is laid directly on the shiplap, it will droop and leak over time.

A Few Considerations Before Repairing The Shiplap Roofing:

The shiplap on your roof indicates that the roof deck is at least 50 years old. It has dried up tremendously at this stage. Because the wood is brittle, there may be gaps between the boards where water can leak.

These planks are prone to cracks and knot holes, leading to leaks. If other shingles were put to the original roof, a new underlayer might be used to hide the shiplap, which can deteriorate over time.

Each layer creates new nail holes in the layers underneath it. Leaking can occur in any hole, fracture, or void. Furthermore, when a new roof is built over the old shiplap, the nails that keep the roof in place do not go all the way through the shiplap. This means that new shingles will not be fastened to the roof and vulnerable to damage and leakage.

Steps To Repair The Shiplap Roofing:

Electro-galvanized roofing nails enter the shiplap while installing new asphalt composition shingles, cracking or splitting the boards and impeding a suitable seal.

These nails push upwards through the newly installed tiles as they expand and contract. Raised nail heads can lead to seepage of migrating water and mysterious leaks. Wind gusts can potentially blow the shingles off your roof if they aren’t properly attached.

Go For The Solid Sheathing:

Why take the chance of installing a roof with a 50-year warranty only to have it leak in a few years? It’s to your best advantage to lay strong sheathing over the existing shiplap for your roofing system to firmly fasten to if you don’t want to go through the hassle of tearing up your new roof hunting for a mysterious leak. Exterior grade OSB boards and CDX genuine plywood are recommended.

Apply An Underlayer Over The Shiplap:

Another popular approach is to install an underlayer over the shiplap, which is prone to deterioration as it ages. This is almost guaranteed if additional shingle layers were put over the original roof. Roofs with many layers of shingles are frequent on older roofs. Each layer leaves a trail of nail holes in the layers beneath it. Each new hole, crack, or void increases the chances of the roof leaking.

Another concern with building a new roof over shiplap is that the nails fastening the new roof aren’t sunk into the shiplap, leaving the new shingle unsecured to the roof. This allows wind and rain to damage the new shingle and cause it to leak.

Install New Substrate:

Removing the entire roof and starting over with a new substrate, vapor barrier, and shingles is one option to tackle all of these issues. Shiplap removal is time-consuming and costly. Resheeting directly over the shiplap with exterior grade plywood is the most efficient and cost-effective alternative.

This is approved by both the code and the roofing manufacturers. Your new composite shingle will be securely fitted to the new solid surface and will not leak for years. Your home is your most valuable asset. And when you need a new roof, it must be properly fitted.

Consider The Professional Roof Repairing Services:

You should avoid roofing contractors that cut corners, and if you come across one who thinks it’s permissible to build a composition roof on top of shiplap, politely decline. In the future, your roof, as well as your peace of mind, will reward you.

If your property has shiplap, the best thing you can do when reroofing is demand that your roofing contractor installs new plywood sheathing/decking to avoid a costly and time-consuming repair later. Under today’s roofing industry standards, this is the most reliable and proven technique of reroofing your home.


You’ll need a trusted roof repair firm when your home needs a new roof, repairs, or upkeep. Your roofing contractor is responsible for keeping your home secure and dry. Hopefully, this article will guide you to repair the shiplap roof effortlessly and efficiently. However, it would be best to hire professionals to repair the shiplap roofing appropriately.

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