How many layers of shingles is too many?

A common question among homeowners is "When is it time to replace my roof?" This is no small decision, as a whole roof replacement can be costly and somewhat of an inconvenience (though not as inconvenient as waiting too long and suffering the consequences). One important factor to consider with regards to that matter is the number of existing layers of shingles on your home.

When your home was first built, only 1 layer of shingle was installed. This one layer has been designed to be able to withstand general wear and tear for a number of years (depending on the quality of shingle that was installed). When that first layer of shingles stops doing its job sufficiently (tabs missing due to wind, heavy granule loss, or noticeable water damage on the home’s interior due to water seepage through missing tabs), a roofer has 2 choices: remove all existing shingles and install a fresh layer, or put new shingles on top of the old. Either option may be appropriate depending on your circumstances, however reroofing will be much cheaper, as tearing up the old roof increases labor costs plus the cost of paying for and installing new underlayment (and sometimes new decking). Disposal fees would be higher as well.

That being said, putting a second layer of shingles on the original layer is accepted by some roofers and not accepted by others. Many believe (as I do) that the best course of action is to strip of the old and apply all new shingles and underlayment. If you simply apply a second layer, there may be underlayment or decking issues that would be otherwise unseen and unaddressed.

When it comes time to reevaluate your roof’s status and there are already 2 layers there, then your decision is a little more involved. Most building codes allow two layers of organic or fiberglass asphalt shingles on roofs with a 4/12 pitch or less, and three layers on steeper roofs, if the structure can support the added weight. Three layers of shingles gets to be fairly heavy, and if your decking is unable to bear the weight, or if the pitch isn’t steep enough, this can lead to problems down the line such as damaged or sagged decking which leads to water damage inside the home. So a third layer of shingles is usually not the best decision and is in some places illegal. It is sometimes the result of lazy roofing, where a contractor takes the less laborious route when they don’t want to go through the trouble of tearing off old materials.

You may occasionally come upon a roof with more than 3 layers of shingles. This is never legal and never in the homeowner’s best interest. According to the Housing Handbook: Requirements for Existing Housing One to Four Family Units 4905.1 on HUD.GOV:

2-12 Roof covering must prevent entrance of moisture and provide

reasonable future utility, durability and economy of

maintenance. When reroofing is needed for a defective

roof, already consisting of three layers of shingles, all

old shingles must be removed prior to re-roofing.

Furthermore, Per VC (8/99) form page 2 of 4 under section VC-9 Roofing reads:

HUD/FHA requires that the roof have at least 2 years remaining life. If the roof has less than 2 years remaining life, then the appraiser must call for a re-roofing or repair. The condition must be clearly sated whether the subject is to be repaired or re-roofed. FHA will accept a maximum of 3 layers of roofing. If more than 2 layers exist and repair is necessary, then all old roofing must be removed as part of the re-roofing.

Don’t let yourself get taken advantage of. Know the law and your local codes so that you get the service you are entitled to. One final note, don’t forget that many types of roofing damage are covered under your home owner’s insurance. So before deciding to fund the whole project yourself, have an adjuster come out and appraise the damage. It could save you thousands out of pocket in the end.

Andy Breivik is a claims manager for TriCounty Insurance Restoration, serving Roanoke and surrounding counties. For a free estimate, visit tci-restore.us