Does your asphalt shingle roof have spots that feel spongy? If so, you shouldn't ignore them. Moisture is the leading cause of soft spots on an asphalt roof. Spaces between the shingles allow moisture to infiltrate the roof and soak the substrate underneath the surface. The soaked substrate rots and weakens the shingles. This creates spongy areas that easily crumble to the touch. Read on to find out four issues that may arise if you ignore soft spots on the asphalt shingles. 

Water Damage on the Plywood Sheathing

Plywood sheathing boards are affixed to roof trusses and joints to help distribute weight evenly across the structure. Sheathing plywood isn't waterproof, so contractors use waterproof varnish to prevent water exposure. However, if your roof has broken or missing shingles, moisture can seep into the plywood and gradually deteriorate the waterproof coating. Moisture causes the plywood to swell and split or rot. Therefore, you should replace the damaged sheathing sections before replacing the worn shingles.

Sagging Roof Deck

If you fail to fix broken or missing shingles on your roof, moisture can soak the sheathing and infiltrate the roof deck. If your roof frame isn't pressure-treated or sealed to keep out water, the wood will absorb the moisture and expand. Prolonged exposure to moisture can deteriorate the wood, causing the deck to sag in some areas. When this happens, you must replace the water-damaged wood and reinforce the structure. You should also seal the wood with a durable sealant to keep out moisture.

Extensive Shingle Damage

Asphalt is used in residential shingles due to its water-resistant properties. However, this doesn't mean moisture can't damage your roof. Once water infiltrates the sheathing and gets absorbed by the deck, it weakens the frame and causes the fasteners to withdraw from the wood. Fasteners securing the shingles to the sheathing can also fall off once the plywood weakens from moisture absorption. Consequently, the shingles are left with no anchor and can be easily blown away by strong winds. If the damage spreads across large sections of the structure, you may need to replace the entire roof.

Rot on the Soffit and Fascia Boards

Soft spots on the lower parts of the roof can result from clogged or inefficient gutters. Blocked or failing gutters allow rainwater to back up on the roof and drip on the soffit and fascia boards. Since these boards are made of wood, they can absorb moisture and develop rot or mold. Therefore, besides repairing the roof, you should replace the deteriorated soffit and fascia boards.

When caught early, soft spots on the roof can be fixed by replacing the water-damaged sheathing and missing or broken shingles. Therefore, contact a local roof repair service to learn more.