A friend of ours just purchased a new home back in March of this year and they are having some concerns with their roof. Since the home is less than nine months old any problem with the roofing should be a concern to the new owner. Normally when problems show up this early it means that they won’t be getting better over time.
As you can see the problem they are having is Telegraphing of the Roof Trusses through the Shingles. This is a pretty common problem that happens when the workers installing the roof and shingles aren’t following proper procedures. Because the shingles were probably installed by a roofing contractor you can’t really place the blame on them but we will go over what the most likely things that are causing this problem.
Why Do Roof Rafters Show Through The Shingles?
There are a few reasons that roof rafters or roof trusses would show through the shingles of a completed roof.
The first is the use of the wrong type of fastener. When you install roof sheathing plywood you are suppose to use at least a 2-1/4 inch ring shank full head nail. Both the length and the presence of a ring shank are important. Many contractors will use a common nail that is glue coated and this is not enough when applying roof sheathing. Ring Shank nails grip into the wood somewhat like a screw and won’t easily pull loose. Another factor is the use of a full head nail. Although there is debate on whether a full head is any better than a clipped head nail when it comes to fastening that debate ends in framing of walls. When you get to applying sheathing on a roof the extra security of a full head nail is worth the cost of having to refill your gun a little bit more often. This is the reason clipped head nails are used because you can fit more of them in a nail gun and that reduces your need to refill your gun as often.
The next reason would be not spacing or gapping the sheathing plywood an 1/8th of an inch when you install it on the roof. Because your attic will be filled with a lot of very hot moist air and the roof sheathing is going to take the brunt of the heat it is very important to allow for expansion. Not allowing for expansion of the plywood will mean as the sheathing swells it will butt up against the next panel and possibly pull away from the truss.
Is The Roofer Or The Carpenter To Blame?
In this case you can pretty much say that the carpenter that put the roof sheathing on was to blame for this problem. Most likely they used common nails and not ring shank nails and they didn’t gap the plywood an 1/8th of an inch. If you follow along the roof you don’t see a line from the top to the bottom but you see four foot lines that are offset. That means the panels are pushing together when they swell from the moisture and heat.
If the roofer caught this problem they could have reduced their call back by telling the site manager but its pretty likely the site manager is just going to tell the roofer to lay down the shingles and get it done. If I was the roofer I would have wanted a signature from the general contractor eliminating my liability on the call back.
Final Note
If you have a brand new home then you should have a warranty of workmanship and if the workmanship causes problems with the materials then the total cost should be covered.
In this case the shingles will have to be removed in a few areas to really get the full answer but just because the shingles are the top layer of the roof it can be really easy to blame the roofer when it was really the carpenters that caused the problem.
Something really tiny like that can mean a lot down the road and hopefully because the house is less than a year old it will get fixed without too much argument. This is obviously something that isn’t going to go away any time in the future and it will cause the roof shingles to fail much earlier.