Did you know that a new roof can raise the resale value of a home by approximately $12000? Well, a roof is more than shingles that are visible from outside.
It just the most visible part and an important feature that gives the home some edge as well as keeping the dweller safe.
A roof comprises three main components; the deck, the underlayment, and the shingles.
Underlayment also protects your home from damage caused by rough weather conditions like heavy rains, ice, or snow. Less known or talked about is the roof underlayment types that lies beneath it and the second in the line of defense in the protection of the building. It plays a role in preventing damages and leakages in a building. It also protects the deck from deterioration by chemicals from the shingles.
What is Roof Underlayment
Underlayment is a layer of material used as a barrier to keep water from penetrating through incase the outer roof (shingles) is damaged. The underlayment is placed between the roof deck and the visible outer roofing material.
When water gets trapped under the shingles, it can leak through the deck. This not only caused damage to the deck but to the ceiling as well. The purpose of underlayment is to ensure that that water does not pass through to the deck.
It protects the deck from water damage before the shingles are installed. Its use is believed to have originated from the use of tar paper. This material was used by miners during the California gold-rush in the early 1800s to roof their temporary structures. The use of tar paper as an underlayment was then born. It has since evolved and advanced to three main types currently, as discussed in this post.
Why Roof Underlayment is Important
When installing shingles, one cannot fix directly onto the roof deck. If this were to be done, any damage to the shingles would cause water to sip right onto the deck, destroying the building. This kind of damage is not only a health hazard but also devalues a building. A good underlayment should give a home a healthy lifespan and minimize the cost of repairs.
Let’s have a deeper look into roof underlayment now.
Roof Underlayment Types
The main types of underlayment are as below:
- Asphalt-Saturated Felt Underlayment
- Non-Bitumen Synthetic Underlayment
- Rubberized Asphalt Underlayment
Pros of Asphalt-Saturated Felt Underlayment
- It is relatively cheaper
- Good for hot and dry weathered states like Arizona
- Readily available
- Has been tried and tested by time
- Slope limitation requirements that allow overlap giving a double layer for enhanced protection.
Cons of Asphalt-Saturated Felt Underlayment
- Has a shorter life span of around 15-20 years
- Hard to install due to its lack of elasticity
- It is not waterproof
- Gets easily destroyed by heat from roofing material and severe sunlight
- It is heavy and comes in two varieties, 15 pounds and 30 pounds.
Pros of Non-Bitumen Synthetic Underlayment
- Easy to install and has an anti-slip surface
- More durable and can last up to 12 times the lifespan of asphalt
- It does not absorb moisture, therefore, prohibits the growth of fungi and mold
- It is light in weight
- It has a longer lifespan of 25-30 plus years
- It is made of polypropylene and polyethylene, materials that can be recycled.
Cons of Non-Bitumen Synthetic Underlayment
- It is quite pricey and can cost five times more than asphalt, making it least ideal for low budget builders.
Pros of Rubberized Asphalt Underlayment
- The only underlayment that is waterproof
- It is easy to install because it is self-adhering
- They have a long lifespan
- It is highly resistant to the sun’s ultraviolet rays.
- Easy to repair.
Cons of Rubberized Asphalt Underlayment
- It is expensive
- Heavy and thus labor extensive
Choosing the Best Roof Underlayment Type
When it comes to choosing underlayment, a lot of factors have to be considered. The lifespan of an underlayment is an important factor to consider. If there are plans to change the entire roof soon, one that is cheaper and with a shorter lifespan would be a better choice.
I found synthetic roof underlayment is best among all. It’s lighter than the rest. It is also more tear-resistant when being installed compared to asphalt felt underlayment.
However, the synthetic roof underlayment is quite expensive. If the budget does not allow, go for what is suitable for you by looking at these other factors.
The local climate should be a major factor when considering the type of underlayment needed. Different materials react in different ways when exposed to too much heat or water. In New York, for example, the weather ranges from cold and windy to warm and humid. This means that the underlayment gets exposed to more moisture, which will eventually affect it. You cannot use the same underlayment material in areas with severe rainstorms, snow, and ice as those that are relatively dry. Florida and Texas are not just same.
The roof design can affect the performance of an underlayment. The roof’s ability to remove water or moisture. Some prevent water and moisture from getting trapped. In contrast, others trap it, exposing the underlayment to too much wetness, leading to a significantly shorter lifespan. Low sloped roofs should need a more water-resistant underlayment because of their inability to drain water properly.
Choose an underlayment that goes with the roofing material. Incompatibility can cause damages to the underlayment. Having a poor rooftop can weaken the functional capability of the underlayment and efficiency. The roofing material should complement the underlayment.
In Florida, the building Code forbids the usage of No. 15 felt asphalt. However, it allows the use of the heavier No. 30 felt asphalt, but that can only be used if applied in two layers. This code has pushed many homeowners and developers to seek alternative underlayment types. So, complying with local laws is important.
The contractor hired to install the underlayment can make or ruin your roof. Suppose the installation of the underlayment is poorly done. You will undergo damage to the deck, and so the entire building. Bad installation methods can damage the material as well as premature failure.
The use of plastic caps and roofing nails are recommended. Staples often leave room for water to penetrate the deck.
The underlayment should wrap around the edges to avoid water penetration and moisture, causing damage to the structure. Remember, synthetic underlayment is not self-sealing and so the need to wrap around the edges. A good contractor will ensure the installation is done right.
The underlayment may be a good choice in all other aspects but maybe beyond one’s budget. The funds available by default will influence the choice.
How to Inspect Roof Underlayment
An underlayment inspection is done to determine the underlayment’s integrity and how long it will last. The inspector is likely to check the ceiling and the attic to determine the underlayment’s general condition. If there is an indication that it is damaged, a detailed inspection can be carried out.
Roof repairs can be costly but what will cost more is to replace it entirely. It is advised to do a regular inspection and ensure the roof’s right condition at all times. This keeps one conscious of the status of the underlayment. It is practically impossible to inspect an underlayment only without touching the roof’s other components.
Underlayment inspection and general roof inspection should be carried out at least twice a year and after an extreme weather season or storm. The owner can do a primary assessment. However, a professional roofer is required when the underlayment inspection is for insurance or sale reasons.
Aa a homeowner you should:
- Look out for visibly damaged outer roof
- Clean the gutters regularly
- Inspect the attic for signs of water seepage
- Look out for areas with potential water damage
Perform a roof underlayment inspection when you notice:
Water Stains on the Ceiling
Water stains on the ceiling are a telltale sign that the underlayment is damaged and water is leaking. It can signify the weakening of the underlayment due to age and other factors.
Missing or Curled Shingles
If some shingles are missing, it is good to check the underlayment to ascertain if there has been any damage. Missing or worn out shingles mean that the underlayment is contacting more water than is desired.
When to Inspect Roof Underlayment
If you are buying or selling a home, an underlayment inspection is important for insurance and valuation purposes. This is to determine its condition because a roof carries a lot of value. It helps to know the amount of work that the underlayment may need. Also, after every season or when you sense the need to inspect.
Cost of Roof Underlayment Inspection
According to homeadvisor.com, a primary roof inspection ranges between $119 and $303. The costs may vary depending on; climate, the size of the home, the reason, and the amount of expertise required.
An underlayment inspection can be used to determine the followings:
- Whether an underlayment is installed according to the right specifications. The overlapping may have been incorrectly done or the sealing around chimneys and the roof edges.
- Whether there is any damage to the underlayment. It can be caused by tears while installing and holes caused by fasteners.
- Whether the underlayment is compatible with the roofing material.
- Whether the underlayment needs to be repaired or replaced.
- The age of the underlayment and estimated lifespan
- If the underlayment is a hazard in any way
- The value of insurance policy
- A portion of the value of a home
If a roof is not functioning as it should, the whole building is affected. A good ceiling is essential to any building. When selecting a roof underlayment types, there are many factors to consider. The underlayment of choice should be a balance between all these factors.
Without proper roofing, even a good home can get ruined, and its quality brought down. It can also put a household at risk of dangers brought by extreme weather fluctuations and other exterior factors. The underlayment, though not visible, is vital to any roofing system.
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