I live in Bothell in a shake roof rambler. When I replace my home's roof, what actual parts of it get replaced?
This is a great question, as most houses roof infrastructure lasts for as long as the house lasts. You’ll notice that often, ‘replacing a roof’ means the replacement of the tiles (or that layer that is visible), the water proof layer under it, but usually not much more. Under those two layers, however, there is a lot more of the roof structure. You have the roof’s rafter and joist structure. That’s that part that looks like – from afar, at least – it is made of matchsticks, all neatly secured together, but certainly not enough to protect your house on their own. Over that framework, plywood is usually secured. It should completely cover the infrastructure and, usually, does not need to be replaced. It’s only when there is actual and sustained water leak damage that some or all of that plywood layer would need to be replaced.
The top two roofing layers: tiles and waterproofing
Provided there is no water damage (or insect, bird or plant damage) to the anything under the top two layers, all you should need to replace is the tiles and the waterproofing layers. The price of that, of course, depends on materials, size of roof, and any extras you might include in the bid. Prices vary, too, by region. Costs are higher in some areas simply because everything costs more. Where rents, taxes and other costs are higher, the cost of replacing a roof will be a little more, too.
In most roof ‘replacement’ projects, the tiles are removed and discarded, the plastic or vinyl layering under it is also removed, and the exposed plywood is clearly visible. At this point, it is easy to see if there is water or other damage necessitating the replacement of any or all of it. In small leaks which have been chipping away at the plywood for years, the damage can actually be quite extensive. In fact, it might have reached into the infrastructure underneath it, or into other parts of the house. In some cases, a leak is only noticed years after it began, by which time is is dripping small drops onto, say, your kitchen table. A few drops on your kitchen table may mean serious damage higher up in the building. And if it has been going on for years, there’s no telling how much damage there truly is.
Assuming there is not further damage, the vinyl / plastic layer under the tiles is secured to the plywood. There is a particular skill in this part of the work because it forms the only true barrier from the elements. All the other layer play, as it were, supporting roles. There is a specific type of nail that is used to secure the vinyl layer to the wood roof under it. It has to be done properly so that water does not make its way through the hole that you must necessarily make. Not all nails will do the trick.
Tiles are the last layer, although if you are using real wood shakes, it is advisable to add a protective layer of sealant on top of that too. Cedar does have some natural protections against the rain but eventually, it will decay. An extra coat of sealant will make the difference by adding years to the life of your roof.
A roof inspection every two years will catch problems while they are still small
A stitch in time, they say, saves nine. Nowhere is this axiom more true than in the roofing business. If you find a small leak today – perhaps it sprang in the storm last week – fixing it might cost $200. If you ignore it, and it lets water slowly enter into the interior of your home, it can do a lot more damage over time. Perhaps it rots the entire ceiling structure of the upper floor of your home. How much might that cost to repair? Hard to tell. That’s why it’s wise to get a roof inspection every few years. And a roofing company is usually eager to take on the roof inspection – often for free – if they are the first to offer a bid to fix anything they find. If there’s a problem that needs fixing, they will find it. This is not to be mistaken for a house inspection. In a house inspection, they have a lot more to cover, and may not have specific and deep experience of what problems may occur in a roof. The same is true of electrical wiring, plumbing, sheet rock, and other elements of a home. To do a roof inspection, you need an actual roofing company. Schedule one for every few years, and don’t skip over it when the time comes.
Take your roofing company’s advice
Although roofing wouldn’t be described as rocket science, it is one element of your home which, if it is improperly done, can cause damage far in excess of the cost of doing the roof right in the first place. When the roofing project is completed and you’re shaking hands with the roofer on the last day of the job, talk to him or her about what they would advise for your house going forward. Are there any tips regarding ventilation? Insulation? What further treatments you could benefit from? A quick conversation is worth it. Right there and then, add an appointment to your calendar to call them again in two or three years for the first post installation inspection.
You’ll thank me later!