Plywood ‘vs OSB (Waferboard)

Sometimes choosing the building materials that suit us is a difficult decision. In the case of plywood ‘vs OSB, it’s a no brainer.

The home is a system, exterior claddings, framing and insulation, and interior claddings that all interact with each other on some level. The most important variables playing into this equation are: Air movement into and out of the building envelope (factoring heavily into heat loss), vapor transmission to and from the building envelope, and strength.

Air movement- how drafty your home will be- is the same for either plywood or OSB, theoretically speaking. The most important thing to remember is to properly nail the plywood on the outside walls and roof. That means extra nails at all edges, and adjusting the depth setting on the framing gun from super deep setting for framing, down to relatively shallow for shooting ply or OSB. Otherwise, your nails will blow most of the way through it and you’ve lost strength.

Speaking of strength, there is a difference between OSB and plywood. I’m no engineer, so let me relay my personal experience. I was fresh out of high school in the early 90′s and learning about framing houses on the coasts of Beverly and Marblehead, Massachusetts. We often had to build to withstand hurricane force winds, incorporating shear walls to resist lateral wind pressure. When we built the walls laying down, we had one of two choices for bracing it against the wind (no complaints about Bob Seger stuck in my head right now). We could use plywood and lay the sheets across the studs and stagger the joints every four feet in each successive course of real plywood and the stength of the plywood would brace the wall; or, we could cut diagonal bracing into the wall studs from top plate to bottom plate before sheathing with cheap-o OSB. Hopefully this information gives some perspective as to strength.

Next is vapor transmission. This is slightly more involved. Wood can absorb moisture just fine and, when allowed to properly dry out, can repeat this cycle indefinitely. It becomes a problem when the wood doesn’t have the opportunity to dry out. Therefore, the drying process is critical.

Your home is built almost entirely out of building components that hold moisture. The amount of moisture that they hold depends on: The types of materials used, the amount of humidity created by inhabitants (about 70% of a home’s humidity is from occupants cooking, showering, watering plants, dog dishes, perspiring, etc.), the relative humidity in the atmosphere, and of course the amount of air flow in and out of the home.

To allow the home to dry out, we must allow for slow vapor transmission through the building materials. This is why we should never use a vapor barrier on the warm side of a wall system. We don’t want to block all vapor diffusion. This would cause the vapor to hit that sheet plastic “vapor barrier” and condense, with no where to go. After condensing, the next step would be mold.

 

What we need to incorporate into walls and attic floors are vapor retarders that simply slow down vapor diffusion. We must allow the building and all of it’s components to dry out. So, we don’t use sheet plastic on the inside of the walls. Fine, but what does all this have to do with plywood versus OSB? Well, I was laying down a little building science theory, necessary for understanding the importance when choosing a wall or roof sheathing.

If we want to allow the building to breathe, which is the better choice? OSB is made up of wood wafers and glue, then treated with a film of wax to buy some time for exposure to the elements during construction. OSB has a perm rating (the means of measuring how much vapor will pass through a material) that remains very low and constant. When the relative humidity rises, it continues to allow the same miniscule amount of vapor to pass through it.

Plywood, on the other hand, has a decent perm rating and is able to ride a very nice curve. It is made of real, unpulverized wood layers that are glued together in opposing grain directions with an exterior glue. Because it is real wood, when the relative humidity rises, it’s ability to allow vapor to pass through it rises in kind. It allows the home to dry nicely under normal conditions.

Next, let’s talk about mold. Mold is a fungus. Fungi need food. Wood can be food, especially when sopping wet and beginning to break down. Additionally, when wood is pulverized, a sugar like byproduct is created. This is sugar like to mold. Oh wait. OSB is made up of pulverized wood and glue. The more and more that wood is pulverized down, the more sugary wonderful it is to mold. That’s why mold will very easily grow on the paper facing of drywall in a moist bathroom. OSB is far more susceptible to mold than plywood.

Let’s round this out by talking about the all important bottom line. OSB for wall sheathing can cost less than half of what plywood is going for. Let’s say we’re building a decent sized two story addition requiring 70 sheets of 1/2″ sheathing for walls and roof. At current rates, it would cost $525 for OSB and $1,330 for plywood. Now knowing this building science, who would choose to save the $805 and go with OSB?

Let’s consider two more things: Interior subfloor application over floor framing, and the introduction of red type (roofs) and green type (walls) super waterproof OSB sheathing.

First, the easy one. I always use OSB for interior subfloor applications. For this, we are inside of the building envelope and vapor is not struggling to pass through it. It also is cheaper and flatter for floors, making it a great choice and a green choice.

Finally, let’s discuss the introduction of super waterproof OSB. This is becoming incredibly popular for builders. I will never use it. First, you’re still not allowing the home to dry out properly via vapor diffusion. Second, it doesn’t adhere to the most fundamental of all building principles: Every single building component should be overlapped by the one directly above it in elevation. This utilizes the physics of gravity to keep the home dry and has been successful for centuries.

Then how does this other system work? First, the OSB is coated with some special magic potion to keep water out. Fine, wonderful, remembering that this also means that it keeps vapor in. What about the joints between sheets? Well, this is the kicker. It means that the carpenters must use a special- and expensive- proprietary tape gun to apply the special tape to the seams. That’s where we no longer overlap materials. You see, with plywood or regular OSB sheathing, we apply a rainscreen over the sheathing, such as tar paper or Tyvek, etc.. We overlap this rainscreen, maintaining the most fundamental principle of building. Conversely, the tape that is applied to the special OSB relies entirely on adhering over the surface of the plywood, a non glossy surface.

If you hang out at the lumber yard long enough, you’ll hear other guys asking what to do when their finicky tape gun no longer works properly. They dread shelling out the big bucks for a new one. Yes, these applicators don’t always apply the tape to create a watertight seal. And what if the sheathing has a film of sawdust on it’s face? I don’t know, you tell me. If you pay attention to addition jobsites, builders that are using this new super OSB with the taped seams on a roof with a finished living space underneath are still tarping the roof until they get the shingles on  it. How much confidence do they seem to have in the product they are using on the roof? When roof plywood, on the other hand, is properly covered with ice and water shield and roof underlayment paper such as synthetic tar paper, the building will stay dry during construction every time.

Why would the lumber industry offer a product like this? Because they want to sell to the ever growing demographic of builders that don’t understand how to properly and permanently water proof a building. The lumber industry is dumbing down the products. Yes, we should all write our representatives in congress.

In conclusion, plywood made of real wood is by far the best thing for your exterior walls and roof. It only needs elementary attention to waterproofing details, and will then allow your home to breathe properly. OSB is the best choice for interior flooring substrate.

This material was largely a result of an education from Joseph Lstiburek, Ph.D., P.Eng., ASHRAE Fellow. He has been widely renowned as an international building science expert for decades. If you want to learn more about building science or cure insomnia I’m just kidding, some of the writings on the site are actually very entertaining), visit his website at http://www.buildingscience.com.

 

By John Bradshaw

 

 

 

Seeing Red

As you look at the roof, the right portion has been pressure washed already, but the right portion not. You can also see that the butt edges of the shakes that have already been washed will need a quick zip over them with the stiff bristle brush. We don’t want to be too aggressive spraying up at these butt edges. Also notice there are a few small shingles under the bottom of the skylight flashing that we’ll have to re-nail. Plan on a little bit of that.

I was recently contracted by a long time homeowner in Newcastle, NH to go through the exterior of his home and look for problems and areas needing attention in anticipation of putting the home on the market in the spring time. He only spent a moment with me, just long enough to mention that he wished he could get the cedar roof replaced for less than $30,000. Then, he left me to evaluate the home and report back.

This assignment threatens me with an anxiety attack every time (fortunately, I’m not prone to anxiety attacks). I never want to tell clients that they have unexpected problems. This home happens to be just a touch over twenty years old, not an era renowned for fine craftsmanship.

Good news: Nothing more than a handful of rotten trimboards, seal the chimney, clean the moss and lichen build-up off the roof, and we’re home-free. I delight in reporting that the home was very well built.

So, we took care of the rotten trim, sealed the massive chimney, and treated the moss build-up with ‘Wet and Forget’. The problem was that the moss build-up was so entrenched that I estimated that it would not just wash away over time after this treatment.

The homeowner was really concerned about the roof, and rightly so. I eased his concerns a bit by stating that the cedar roof is actually in great shape and has another decade of life ahead. Buh-hut, I also had to offer that roofs, windows, and heating systems are the 3 big ticket items that either turn away prospective buyers or take $ out of the seller’s pocket. He agreed 100% and asked what I could do about it. “Well, we could pressure wash the roof. It would tear off the old and dead skin cells, so to speak, and reveal the beauty underneath. Let’s exfoliate your shingles!” The reason we could pressure wash his shingles is because they are California- Hand – Splits. They’re about twice as thick- and irregularly shaped- as regular cedar shingles. He jumped on board, and then one-upped me, “Then, we could spray the ‘Wet and Forget’ on the roof to prevent future build-up.”

Sounds enough like a winning plan, now we just have to execute. When wet, the roof is like a ‘Slip and Slide’. We would have to use roofing harnesses and walk it with the pressure washing wand to clean it. We started a pool to see how many times I would slip and eat cedar shingles on day 1. Only twice, and they weren’t half bad. It was actually pretty rewarding to turn a client’s old roof into a new roof. But, it was mind-numbing work.  Not that the work I do is rocket science, but every now and then it’s nice to have a non-cerebral day. I only wish I had chosen a better last song. The last song I listened to in the truck was Def Leppard, now stuck in my head like the guy in the x-ray that didn’t see the javelin coming.

This back side of the garage roof took me about 5 hours to wash. This is after drying.

On day 1, it took me 5 hours to pressure wash a section of roof measuring approximately 30 feet wide by 16 feet up. It took an additional hour and a half to spray it with the “Wet and Forget” to keep moss and lichens from building up again. Remember to test out which tip to use with the sprayer so you don’t tear apart the soft cedar, and try not to spray uphill too much, this could cause leaks, obviously. Also, keep in mind that cedar turns gray in the sun, no matter what. So if you’re thinking it’s going to look like brandy spankin’ new forever, you may want to rethink that.

This is the front side of the garage after washing. We usually ask clients to at least shut their car doors before pressure washing above.

If you’re thinking about doing a project like this, please remember that a bit of pre-planning can go a long way. Don’t let Def Leppard pour sugar on you all day long! Enjoy.

 

By John Bradshaw

The Most Common Roof Error I See

Photo #1- This home in Portsmouth features an outside corner to the immediate left of the trash barrel that is exactly the scenario most likely to be done wrong. The inside corner that’s just a touch up the roofline is also a common culprit.

Photo #2- If you click on this image to enlarge it, you will see there is a gap between the copper step flashing going up the roof line and the horizontal copper apron flashing.

You may have learned by now that I’ve never been known for brevity. This blog post, however, should buck that trend a little bit. Why? Simple, because this common error is very easy to identify and resolve. So easy, in fact, that it doesn’t make much sense why these things are almost never done properly in the first place.

The scenario is this: Any time an out side wall corner or an inside wall corner comes down to intersect with a roof plane, assume it’s not flashed properly. Now, this does not mean that it leaks, necessarily. It may not leak due to a proper insurance layer of ice and water shield underneath the shingles. Conversely, the lack of water signs inside the corresponding portion of the home does not mean that it is not leaking. Wood, especially real wood as opposed to “particle board”, has the ability to absorb water, and then dry out. This can happen over and over again, as long as it can dry out. Or, The initial plywood and framing components that are coming in contact with the water that is infiltrating are sometimes not able to properly dry out, and thus rot. The components that lay below these “first absorbers” will get wet, but not necessarily beyond their saturation point. If the lower levels of wood are absorbing the water without exceeding their saturation point, the water may never make it to the drywall layer to display to the homeowner that damage is being done. This explains how a home can be taking on water without showing signs of it on the drywall, for instance.

Photo #3- Just a simple piece of lead flashing to transition between the planes.

What is the error at these corner/roof intersections that is causing these problems? Well, the lack of incorporating nice, wonderful, beautiful, malleable lead flashing into the mix. Am I in love with lead? Maybe just a trifle, but hey, what’s not to love? Standard aluminum step flashing runs up the abutting cheek wall that the roof shingles butt into. And aluminum can sometimes also be used to flash the siding down over the roofing at those wall planes that run parallel with the shingles. But what aluminum cannot ever do is to turn that corner seamlessly. Lead, however, has the ability to hit all these multiple planes seamlessly. Mmmmmmmmm.

Photo #4- This is a home in Hampton. Look how easy this stuff is to spot, yet home inspectors rarely pick up on it, even though this home has stained drywall in the garage underneath.

Photo #5- See the close-up of the hole there. Simple to identify a lack of lead.

It’s comical the things that I sometimes see. I will pull apart these layers to correct and end up seeing layer after layer after layer after layer of aluminum flashing. Each one torn right at the crux of the corner, every time. So, the predecessor’s solution for recognizing that the flashing was tearing: Keep throwing more layers at it. Awesome.

These are flaws that are easy to identify, simple to fix yourself if you’re comfortable on a roof, or inexpensive (unless there is widespread rot) to hire a professional to solve. It may only cost $200- $300 to un-weave some shingles, remove a corner board, install some lead flashing, install a new corner board, and weave the shingles back in. The most difficult challenge you may face might be finding the professional that knows how and when to incorporate lead flashing. Here’s a catchy little reminder when vetting a repair contractor: Find someone with a passion for flashin’. No. I won’t be quitting my day job any time soon.

I must leave you with one last tidbit of information. I mentioned that aluminum can usually be a good flashing choice for the planes that don’t need to wrap around a corner. When it’s not a suitable choice is when there is copper in the vicinity. Copper is ranked higher on the Galvanic Scale of Nobility and blah, blah, blah. Anyway, copper and water runoff from copper interact with aluminum and cause the aluminum to rot right out. That’s also why aluminum is no longer acceptable to use as a deck flashing, because pressure treated lumber is treated with copper. Now you’re prepared to go tackle this one, safely of course.

 

 

By John Bradshaw

 

 

Let’s Play Hide the Plywood

 

This is from my initial assessment.

In photo #2- Do you see the same problem I see?

I was called to a home in Rochester (actually I was emailed to visit this home)to examine recently revealed rot and offer solutions.This home has a second story roof overhang that is almost four feet deep. The homeowner started to find some problems when he ripped up the cement pad that was underneath the entire overhang. The columns had entirely rotted at the bottoms – the home was built before pressure treated wood- so we replaced them. We also replaced all of the fascias with pvc trim and installed seamless gutters and leafguards to manage the water. This proactive homeowner also found some soft and punky plywood after removing some of the siding, himself, to see what was going on.

In photo #2 you’ll see that the major problem I identified was the lack of elevation between the finish grade under the overhang and the wood framing, plywood, and siding. The current building code calls for a minimum of 8″ of exposed masonry between finish grade and framing and plywood. This is to protect the home from water damage and insect damage. With the extra wide roof overhang, there is little threat from water, but major threat from insects. The reason there was no prior insect damage was because the concrete pad was poured right up to the siding. When you’ve seen the devastating damage an underground colony of termites can silently wreak on the framing of a home, you evaluate these situations from a different angle.

In this drawing that I scanned and included with my original work proposal you’ll see 2 things: First, the solution that I’ve been using for a few years now to solve this type of problem; and second, my pre-K art skills not so proudly on display! The foam gasket and the bead of caulking work together to try to form an airtight seal to keep the bugs out. Additionally, we’re wrapping the bottom edge of the plywood with ice and water shield in order to hide the plywood from the insects. I’m no entymologist, but I assume that insects will be far less likely to begin nibbling away at petroleum based products like ice and water shield. The foam gasket must be buried under the ice and water shield. I’ve seen carpenter ants eat away an entire wall’s worth of 1/2″ foam board that lay directly under the siding. The only evidence remaining to prove that it ever existed was the foil facing.

Photo #3- We could stand to add some insulation, since the wall was opened up anyhow.

Photo #4- Insulation beefed up and ready to continue.

 

 

 

 

 

 

 

 

 

 

 

Photo #5

In photo #5, we applied the 7/16″ x 1″ wide foam gasket to the bottom edge of the back side of the plywood. We then began to wrap the bottom edge in ice and water shield. What I did was to gently pre-slice the paper on the back side of the ice and water shield so that I could stick it to the back of the ply and to the foam, but leave the protective paper on the part that will wrap up the front face of the ply.

In photo #6 you’ll see the back edge of the ply wrapped with ice and water shield up and over the foam gasket.

Photo #7

In photo # 7 this is the installation of said plywood panels. Notice I ran the ice and water shield past the first piece of ply, so that I could have good overlapping with the next piece. The process calls for smearing the bottom edge of the ply into a thick bead of high grade caulking. In this case, the local lumberyard didn’t carry Lexel brand caulking (in my opinion the most bad posterior caulking available), so that means 2 things: First, we used Phenoseal translucent caulking (goes on white and dries translucent); second, Ricci Lumber needs to think about opening a satellite location in Rochester, or I need to plan ahead and schedule for them to deliver my sundries along with the lumber order next time. Phenoseal is also amazing, it has my 110% confidence.

Photo #8

 

In photo # 8, note that it’s important to nail the bottom edge of the ply approximately every 6″. Also, remember to set the depth of the nail gun so that the nails don’t just blow 1/2 way through the plywood.

 

By John Bradshaw

Photo #9- Peel off the remaining paper and stick the ice and water shield to the face.

 

 

 

 

 

 

Photo #10- Finish the prep with more ice and water shield tucked all the way underneath components that are directly above.

 

 

 

 

 

 

 

Photo #11- Pvc trimboard installation with hidden fasteners. We also installed proper flashing above the trimboard and replaced siding above that. All that’s left now is touch up paint.

 

 

 

 

 

 

 

Finished product from the road. The homeowner can finish his hardscaping now, sorry Rich.

In summary, when repairing rot in New England, or elsewhere, we must evaluate whether standard operating procedure will suffice. In this case, just nailing up plywood would handle the repair, but not protect the home for the long term. Invest the extra effort to think about and evaluate what forces will be working against the project in the future. Then, find or create the solution that will stand against these forces. It’s an investment you will not regret.

 

 

 

 

 

 

 

 

 

 

 

 

Common Rot Repairs Using PVC Trim Boards

While having the pleasure of working in a beautiful neighborhood in Newcastle, NH recently, I was approached, on separate occasions, by 2 friendly neighbors. Both of these gentlemen were astute “Do -It- Yourselfers” in want of information. All of the homes in the neighborhood were built about 20 – 25 years ago and are beginning to have some of the same issues. They’ve got roofs that are starting to show minor problems, roof boots that have dried out and cracked, windows that have exceeded their serviceable life, and generalized exterior rot. Both neighbors seemed to want to see how we handle some of these things, and determine for themselves whether there is anything of value they might be able to take from it.

Because I want this blog and this website to be a resource, I figure I might as well share my approach to some of these things that people seem interested in learning about. In this case,

This is the bottom trim molding before.

the front door threshold had been replaced at some point with a pine threshold. It rotted at the corners, where the storm door side tracks sit on top of it. Also, the door surround had been patched with new pine in places, and it too was in need of attention. Originally, I didn’t think about writing a blog for this project, so the beginning pictures could have been better.

 

 

 

In this third picture, you’ll see the short section of pine that was used for a previous patch. The predecessor chose clear pine instead of primed finger jointed. Very conscientious. He/she also cut an angle at the top of the piece which created what we call a scarf joint, or some would call a weather cut. This is important. The patch had also been primed on all sides, including the scarf joint at the top. This is even more important when using wood.

But the patch, beginning at the top right corner, had begun it’s rapid descent down the drain anyhow. How come? Well briefly, (I’ll save the real meat and potatoes of this one for another blog post) because pine available today for exterior projects is complete garbage. Be as conscientious as you want, it’s still going to fail prematurely, everytime.

Step one: Drive screw with special driver (no pre-drilling).

So,I chose to replace these vulnerable components with pvc board and trim. Nothing comes without it’s pricetag, however. And these products have their pricey tag.

Additionally, they must be used with the utmost care and attention to detail, or suffer the wrath of buyer’s remorse.

The brand I use is Azek. A 1 x 12

Step two: Set pvc plug.

comes 18′ long and can shrink as much as 3/4″ lengthwise depending on ambient temperature. Typical wood boards shrink and expand with changes in

moisture, and in greatest fluctuation across their width (the 5-1/2″ width for a 1 x 6). Pvc boards shrink and expand with thermal changes, and in greatest fluctuation along their length (18′ for a typical board that is uncut). Therefore it can be entirely expected that if you install an 18′ 1 x 12 that butts into 2 perpendicular wood surfaces on an 80 degree day in the sun, and then come back to visit (this is where being a remodeling carpenter with repeat customers becomes priceless) during November on a

Final step: Gently tap flush with hammer.

40 degree day, you will probably see a gap at each end approaching 3/8 of an inch!!!!

But, with a whole bunch of awesomeness (I’m actually dusting off the tops of my shoulders while typing) these problems can be averted. I’ve built a deck, during the summer, with 1 x 8 trimboards totaling 39 feet joined together. I went back for another stage of construction during the winter, and none of the joints had opened a whisker.

I was very reluctant to use the super-spectacular new virtually invisible fastening method for these products, but with a bit of coaching from some of the younger guys that were more open to these things, I fell head over heels. The screws are made by Cortex. You just sink ‘em deep with no pre-drilling, and then tap in a pvc plug with your hammer. Boom! Nothing ever happened here. Stainless finish nails can sheer off under the right expansion and contraction conditions.

The glue we use for pvc joinery.

What about glue? We should use the Azek brand glue that Azek specifies, right? Wrong-o! This pvc is cellular pvc, similar to being blown up with air like a marshmallow. It’s not dense like pvc pipe. So, Azek specifies a light body pvc cement because it will not “bite into” their trim board too much and thus compromise it, according to them. I’ve seen this proprietary glue fail time after time  (could I please get Cyndi Lauper out of my head now!). I use a medium body pvc cement, preferably in a squeeze tube to fit neatly in my tool pouch. It “bites into” the trim board enough to hold the joint through the changes in seasons. This allows me to create exterior trimwork that water will never have the opportunity to infiltrate. It can join layers of trim on adjacent planes and at perpendicular angles. A trim product that doesn’t absorb water and adhesives and techniques that ensure tight joinery for years to come. I mean, what’s next? Are they gonna come out with commercial free radio stations or something?

Joining the upper wood with the new, lower pvc. Notice the Gorilla glue squeeze out.

The next thing to think about, with regards to this repair project, is joining the new pvc trim patch to the existing wood trim layers. I chose to save the upper portions of the wood trim that weren’t compromised. they will be out of the snow and rain, and I know we can elevate our game to keep water out of these joints. First, the lower product that would be catching all the water will be pvc. Second, we will use relatively small pieces for these patches so that the percentages that they will shrink with thermal changes will have a miniscule practical effect. Third, when we bond them to the wood we will use the best adhesive ever for this application…next time. I loathe making mistakes, and both times I’ve had a hard time reconciling it (laugh with me). However, I chose Gorilla brand polyurethane glue for this particular application, and then second guessed myself. To satisfy the second guessing, I did a test joint with a piece of wood joining to a piece of pvc trim. The next day it was no good. The glue didn’t bite into the pvc and  I was able to force the joint apart with some effort. One of the reasons that I chose this glue, however, was because of it’s expansive properties. The other was because of it’s insane ability to bond to wood. Boil it down, and the glue I chose did not properly bond the two pieces. It did, however, expand to fill the entire joint 100% and form an unbreakable bond with the upper wood part of the joint. So, the wood end grain is well sealed forever, and the pvc trim board underneath it should not contract beyond a hairline. Lovely.

For the longer pvc trim boards, I made new nose pieces at the top that sit underneath the wood trim (For this whole paragraph, I have no pics…this blog post was an afterthought). I applied a heavy bead of Lexel caulk and then screwed these small pieces into the upper wood trim. I then applied a nice bead of pvc cement to the top butt edge of the long pvc board before butting it into this small pvc trim detail. Because we used the proper fasteners and adhesives, this perpendicular joint will not fail.

It’s alright to use stainless finish nails when using small components. Further, the nails are only going to be carrying the load until the glue sets up in five minutes or so.

The last thing to remember is to account for whether or not your pvc trim is going to be painted. It doesn’t have to be, but machine marks must be eliminated. They leave tiny pits that allow algae and mold to build up in. Raw edges, if unpainted and unsanded, turn almost black with these growths. Finely sand or paint all exposed cut edges. Also, paint doesn’t stick to sharp corners, so ease the outside corners of your work with a piece of sandpaper. Lastly, paint doesn’t stick to shiny pvc trim very well. I know, your painter and paint retailer will contradict me. That’s fine. I’ve been in the position to come back around to a project 6 months later, to see how the paint held up. The right paint, according to the manufacturer, didn’t stick. I now recommend gently scuffing the entire pvc surfaces to be painted to remove the “shine” from the board, beforehand. It is a price to pay, but remember that the new pvc trim will hold paint FAR longer than wood will, due to it’s moisture stability.

Finished product…before being painted to match.

By John Bradshaw

What’s the Science Behind Vinyl Siding?

There are lots of pros and cons of vinyl siding. Weighing heavily in the pros list are: It’s very affordable, it installs quickly, it’s virtually maintenance free, it can come re-inforced with foam insulation backer, and there are plenty of colors and styles to choose from. Weighing heavily in the cons column: There is a void of science involved.

Now let’s just get the record straight, I’m no primadonna. I don’t need to build or even repair a home as if it were a baby grand. I don’t utterly refuse to work with some materials out of sheer carpentry snobbery, and I’m equally grateful to be working on a modest single story ranch as I am on an elegant Queen Anne Victorian.

There are, however, plenty of times when I need to lobby for the implementation of fundamental building principles. The cardinal rule of building has always been Water Management. It starts with the selection of a buildable site, is adhered to when determining the elevation of the building, and so on until the end of time.  With regards to this cardinal rule, vinyl siding offers virtually nothing. Does that mean that vinyl siding shouldn’t be used? I don’t feel that way at all. It just means that it’s critical to have a bulletproof “drain plane” behind the vinyl siding. What’s a proper drain plane? It is the proper overlapping of weather resistant building materials (such as tar paper or Tyvek housewrap) to continually carry water out over the face of the home. This technique used to be common knowledge in the trade. Used to be.

Without making this a doctoral dissertation, do I like vinyl siding? Sure. It’s on my first home now. It won’t be the selection for my dream home. But it will be the selection for my final home. Ahh, the circle of life….

 

By John Bradshaw