Kevin: Today on "This Old House"... Jenn: Now that we're adding an addition and patio surface, it's the perfect opportunity to add this stormwater-management system.

Zack: The house wrap we're using has some high-performance characteristics.

I'm here in Switzerland at the factory to get an inside look on how it's made.

♪♪ ♪♪ Man: Ahh.

That's it.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ Kevin: Hey, there.

I'm Kevin O'Connor, and welcome back to "This Old House" here in Ridgewood, New Jersey, where we've got ourselves a Colonial revival built in 1930.

And we're working with some homeowners who want some updates and some additional space.

Now, the demolition has already begun, which means, on the outside, those yellow clapboards that were on the front -- they came off.

We've left the windows, but those are going to get changed out eventually.

And I think Zack and Tommy are probably out back.

Hey, Zack, how are you?

Hey, Tommy.

Both: Hey, Kevin.

Kevin: Look at this.

Concrete's already poured.

Zack: Yeah, so, architect specified a slab-on grade for this addition, so we've got stem wall sitting on the footing, and we're going to set concrete in here.

Kevin: So, what am I standing on right here, Tommy?

Tom: What they did is, they dug a trench all the way around the depth that they needed.

Then they put the walls in and then backfilled by just pushing everything around, compacted it, and put some stone on top of that compact, and that brought it up to the elevation that we needed for the underside of the thickness of the slab.

Kevin: So, when you say "slab," that's what's going to get poured in this dimension right here?

Tom: Exactly.

Kevin: And so is it just concrete or do we have any mechanicals?

Zack: There's going to be hydronic piping included in this to heat the floor, as well as plumbing for the kitchen sink.

Kevin: Yep.

So that's going to be nice and toasty.

Although, I'm a little surprised to see this side-wall insulation on the inside as opposed to on the outside of the stem wall.

Was that by design?

Zack: Yeah, it's true.

The architect actually specified putting it on the inside.

You could put it on the outside, and maybe there would be some thermal benefit there.

But if we put it on the outside, we would have to parge it or do some sort of protective coating.

And the clients are perfectly happy just having the concrete exposed.

Tom: Got it.

Kevin: Alright.

So, this is where we pick up all of our extra square footage for the house.

Tom: Right.

Kevin: Thanks, guys.

Right now, I've got a date with the architects.

♪♪ Hey, Jeff.

Jeff: Hey, Kevin.

Kevin: Nice to meet you.

Jeff: Nice to meet you.

Kevin: So, not your first time working with Zack, but your first time work with us.

So thank you for that.

Jeff: Yeah.

Thanks for having me.

Kevin: Walk me through the plan.

What did the homeowners ask you?

Jeff: So, yeah, they were looking to renovate an existing house and do an addition to give them a little bit more space beyond what they had.

Kevin: Yeah.

Jeff: The existing first floor consists of the dining room, living room, office, half-bath, and kitchen.

A small addition right into the back of the house allowed us to make a number of important changes to the layout.

We moved the entry to the stairs to make room for a coat closet.

The dining room will stay where it is, but now leads to a hallway.

that accesses a new full bath and pantry.

We relocated the kitchen to the addition, which also includes the new entrances off the driveway and a patio area in the back.

On the second floor, we're keeping the three bedrooms as is, but adding a primary suite in the addition above the kitchen.

To keep the budget down, the homeowners opted to just have one bathroom on the second floor that will service all the bedrooms.

On the outside of the house, we're keeping the size and scale of the front intact and only making minor changes, like using fiber-cement clapboards that will require less maintenance than the original siding and new casement windows that will give the house a little more of a modern flair.

As you come around the back of the house, we have large windows on the corner of the addition, creating a modern aesthetic, while taking advantage of the southern exposure and the views to the backyard.

Kevin: And how many square feet are you adding?

Jeff: This is about 500 square feet.

Kevin: So not much at all.

Jeff: Not much at all.

But we are getting a lot into that space.

Kevin: Very nice.

Alright.

Well, I appreciate it.

Jeff: Thanks, Kevin.

Kevin: Thank you, Jeff.

♪♪ Jenn: An important part of a project like this is managing stormwater runoff -- water from the roof, driveway, and grass that does not sink into the ground.

And when you add an extension like this, you need a mitigation plan.

What's the plan, Zack?

Zack: So, the plan is basically to capture all of the stormwater for this new coverage, this patio and this addition, right?

So we start with where the water comes from, the rain, right?

Jenn: Right.

Zack: So we're going to basically capture the square footage of this roof and we're also going to capture the equivalent square footage of that roof, the existing roof, to make up for the additional patio.

Jenn: Okay.

Zack: So we're going to capture those leaders coming down off the gutters.

One's going to be in this corner, one's going to be in this corner, one's going to be over there to capture all that rainwater.

And underground, it's going to go into this large 6-inch pipe.

Jenn: Okay.

Zack: And the reason it's so big is because there's going to be leaves and debris in there.

So it'll be -- Jenn: A lot of volume.

Zack: Yeah, it'll be less likely this is going to clog up.

But then, if this ever fails to work, we have a fail-safe.

We've got waterproofing that's going on the foundation.

And at the base, we're going to use this perforated pipe.

So any hydrostatic pressure that builds up here can go into this pipe, which will be placed down here at the base of the footing as the backup plan.

And hopefully this will prevent any water from ever going into the existing basement, which is lower than the footing drain.

Jenn: Great.

Zack: Alright, Jenn, so, here, I've sort of mocked up this solid pipe.

So this is actually going to tie into that perimeter drain and it's going to tie into this tank.

Jenn: It could be referred to as a tank or seepage pit.

Zack: Seepage pit.

That's a better term.

So, we're actually going to tie in this perimeter drain into these elbows, and they're going to go into the side of the seepage pit.

And then all of the roof runoff is going to be tied into gutters, which will tie into this large 6-inch pipe, which will be at a higher elevation.

So that's actually going to tie in to the top of this.

Jenn: So when it comes in, it's going to flush in here and disperse into all the crushed stone and then percolate into the ground.

Zack: That's the hope.

Jenn: Alright.

So it really looks like this mitigation plan is going to work for you.

Zack: Excellent.

That's what I wanted to hear.

♪♪ ♪♪ Tom: Well, Zack, now that you got the siding off and the windows out, the house is really looking pretty good.

Zack: It is, right?

Tom: Yep.

Zack: So, we got this sheathing all exposed now, but I'm a little worried because it's a partial gut.

I want to keep this house dry.

Tom: Yeah.

So we can cover it up.

Now, if you look at the sheathing, this is 1x8 or 1x10 tongue-and-groove boards.

When these boards went on the house, all these joints were tight.

Over time, the house dries out from the sun, the boards get smaller because of the moisture comes out of it, and they shrink.

And now you have joints that have to get covered.

Zack: Right.

Tom: What we used to use years ago is, we'd use a felt paper, use a 15-, 20-, or even 30-pound felt paper to keep the walls nice and dry and stop some of that moisture from getting into the boards.

Zack: Right.

But today, we're actually going to use this product.

This is a -- like a manufactured membrane.

It's actually self-adhering, so we'll stick it to the house.

But what I like about it is it's really durable.

It's hard to rip it, so you don't have, you know, it blowing in the wind and maybe getting damaged after we install it.

And it's also self-gasketing, so as we put all those nails through, it should keep the house nice and airtight and watertight.

Tom: Watertight, yeah.

And the nice thing about the sticking to the building, it stops the fluttering effect from the walls when the wind blows by, drawing moisture in behind it.

So that won't happen.

Zack: Oh, yeah.

That's a good point, too.

Tom: Before we get started, I think what we should do is tighten up all these nails.

Originally, they were nice and tight, but as the boards shrink in both directions, the nail stays proud.

So it's not holding the board tight to the structure.

Zack: Alright.

And we can snap a chalk line there.

Tom: Okay.

Matches my shirt.

Alright, pull it tight.

Zack: Alright, I'm on the line.

Tom: Go for it.

Got it down there?

Zack: Yeah.

Tom: Perfect.

I'm gonna put the sealer across the bottom here.

Zack: This is a pretty crucial gap because of the way heat works in the house.

It wants to rise up, so if we don't seal this off, it's going to pull in a lot of air.

Tom: Yeah, the heat will pull in the cold air right on that joint where the seal meets the foundation.

Zack: I'm going to tack a few good staples.

And that's going to hold it so that we can peel the backing off of this barrier.

This layer, known as a water-resistive barrier, or WRB, is required by code.

Its purpose is to keep water out of the wall, but also allow any vapor that's inside to escape.

We need to roll it to activate the pressure-sensitive adhesive so it will fully bond to the sheathing.

Because of the way the glue is formulated, we don't have to go through the extra step of priming the sheathing first, which is necessary with some other similar products.

There's a lot of science in a WRB like this, and I was really curious to find out more about it.

And that curiosity led me to Switzerland.

A country known for its chocolate, idyllic scenery, and winter sports, Switzerland is also known for chemical engineering and precision manufacturing.

In this factory just outside of Zurich, they make a number of different house tapes and membranes, including the one we just installed on the project house.

Daniel Schmid.

Daniel: Right.

Welcome, Zack.

Welcome to Switzerland.

Zack: Thanks for having me.

A little noisy here.

You mind if we put these on?

Daniel: Yeah.

Good idea.

Zack: Daniel gave me a behind-the-scenes look at how the WRB we used comes together.

They start with a base layer they call the carrying material.

This cloth-like material is made offsite in massive rolls.

Daniel: As you can see, they are about 5 foot wide and up to 3 miles long.

Zack: The glue they use is formulated from 10 different components held in large vats and then piped into a small cylinder, where it's mixed.

Daniel: I mean, that is basically the result of this mixing process.

So, can you do me a favor and smell the adhesive?

Zack: Oh, should I be nervous?

Daniel: No.

Zack: Honestly, that smells pretty good.

It smells like the glue my 2-year-old uses on her craft projects.

Daniel: Yeah, right.

It is an aqua solution, so that means no volatile organic compounds are emitted during the life cycle of our product.

It is entirely free of toxics, and that is a big plus for our customers, but also for our production employees.

Zack: I mean, it is amazing in here.

It doesn't smell like chemicals at all.

Daniel: Yeah.

Zack: Let's go look and see how they're put together.

Daniel: Yeah.

Now we are in the middle of our coating line.

Zack: Got it.

So that adhesive that we saw made was being piped up and applied to the back of this jumbo roll.

Daniel: Exactly.

And we have worked heavily on the, let's say, efficiency of the drying process.

Let me quickly demonstrate to you what we achieved... Zack: Let's see it.

Daniel: ...in recent years.

So, imagine, in order to dry 1 kilogram of our adhesive two years ago, we require the energy equivalent of this amount of wooden chips.

So that was the initial stage two years ago.

Zack: So, basically, to dry this amount of product, if you lit this on fire and it created energy, it would be that amount of fuel you would need.

Daniel: Exactly.

Zack: Okay.

Daniel: And now, two years later, after having implemented a lot of optimization measures, we only use this amount.

It's more than a 50% reduction.

Zack: Wow.

And why was it so important to get the fuel consumption for this process down?

Daniel: Because it's the production step which consumes the most of energy, the most of resources, and is also the part of production where most CO2 emissions occur.

Zack: Got it.

Once the glue dries on the carrying material, a release paper is laminated to the back.

This protects the adhesive until the moment it goes on the house.

This release paper is made so that it won't tear during installation.

Daniel: Let's quickly demonstrate it.

Can you grab one end of the material and pull?

So, as you can see, it is quite tear-resistant, and thanks to that, it speeds up and makes the application of our product more easy.

Zack: Right.

Because, basically, what we do is, we will stick it to the house and then reach under and peel that away.

And if it was tearing the whole time, it would be quite a tedious installation.

Daniel: Yeah, that shouldn't happen, of course.

Zack: As the large rolls are processed into smaller rolls we use on the jobsite, a precision cut is made that slices through the release paper without harming the base layer underneath.

This shallow cut is less than 1 millimeter deep, and it makes it easier to peel off the release layer during the installation.

The rolls are then packaged, stacked, and ready for shipping.

Like most factories, this one has a testing facility.

Flavio Hunziker heads up the lab that tests adhesives.

Flavio: Welcome in our quality lab.

We are testing here the quality of our raw materials, but also of our finished products.

Zack: Today's test will illustrate how the adhesive strength of the WRB changes over time.

To do that, they apply the WRB sample to a plywood substrate.

A weighted roller helps simulate the rolling that Tommy and I did in the field.

Flavio: And then we straightforward go to the measurement process.

Zack: A special machine measures the precise amount of force needed to remove the WRB from the piece of plywood.

Flavio: It's now tearing off in a 90-degrees angle and measuring the force which is used to tear it off.

Now it's done already, and the machine is going back to initial position, and we can switch now the next sample.

Zack: To prepare the second sample, they applied a WRB to a piece of plywood substrate a week ago and then subjected it to a harsh environment for seven days to simulate prolonged exposure to the elements.

Flavio: So, it was applied one week ago and put to an artificial aging process under a constant temperature stress of 70 degrees Celsius.

Zack: So it's pretty hot.

Flavio: Yeah.

Zack: Okay.

Excellent.

And do you think there will be a substantial difference in performance between these two?

Flavio: Definitely.

Let's check out the samples, starting with the immediate one.

Zack: Right.

Flavio: So, we can clearly see that some of the wood fibers came off already.

And then, also, it's very obvious that we don't have any glue remaining on our substrate.

Zack: But what I'm seeing here is, this is still a good membrane.

If we had to reposition this and put it back, we still could use that.

Flavio: Definitely.

Zack: Okay.

So that's doing what it's supposed to do.

Flavio: Exactly.

So, let's have a look on the seven-day sample.

We can see that the adhesion was higher than the mechanical strength of the membrane itself.

So we were separating the layers here already.

And some of the glue and even some of the back side is staying on the substrate.

Zack: So, basically, it takes a tremendous amount of force to remove this once it's been on for a week.

Flavio: Definitely.

In case you need to relocate something, you can get it off easily within some minutes.

But then, of course, once it's in its final position, it should last for decades.

Zack: Once it's on, it's on for good.

Flavio: Definitely.

Zack: Thank you for all this testing.

I learned a lot today.

Thank you so much.

Flavio: Perfect.

You're welcome.

♪♪ ♪♪ Kevin: Zack, is that you up there?

Zack: I'm up here.

Kevin: Awesome.

I'm here to help.

Where do you want me?

Zack: Maybe come up the stairs.

Kevin: Roger that.

I'll be right up.

Whoa!

Nice demo, huh?

Zack: Yeah.

Kevin: So, this was the old bathroom that's going to be the new, bigger one, right?

Zack: Yeah, so, the new bathroom will expand into the addition.

There will be a toilet, a double vanity, a bathtub, shower, and a chase-way for HVAC equipment.

Because we're changing the whole configuration, I want to restructure the joists so they're going to be strong enough to support the new layout and so the plumbers will have an easier time when they go to do their roughing.

Kevin: What am I looking at here?

Zack: So, this is actually how they did the old prep work for tile back in the day when this house was built.

They would do a mud job, so a mortar base, and then they would have it sit in these bays so they could pack it in.

So, you would have maybe 5/8 of an inch of mortar here and an inch and 3/4 of mortar there, and it'd be a nice solid floor.

A lot of times, when people see people remodeling bathrooms, they leave that mortar in there, but I find it's better to just to get rid of it.

It's a lot of extra weight.

I think the first thing we'll do is, we'll remove the rest of this, and then we can start figuring out how we want to sister this up.

♪♪ ♪♪ Kevin: Mike, this is coming to you.

♪♪ Zack: Alright, so, I'm gonna put this laser level on here.

Now what I'm looking for is the highest point of the joist we're keeping, which, in this case, is going to be this double.

So we have to see if the new joist, which is 7.5 inches, will fit in that pocket.

And it looks like it's going to be a little bit tight, so we're going to make a notch on the bottom of it to allow it to slide in there.

And down here, we can see it's about 3/8 of an inch lower, so we're going to put a 3/8-of-an-inch notch in the top of our new sister joist to raise it up.

Alright, so, what we're gonna do now, Kevin is, I made two marks.

We're going to cut these two joists out.

I've already supported this side of them.

This side we'll remove, and then we can have easier access to sister up that other joist.

Alright, Kevin, so, the first fasteners I'm putting in I'm going to drive in at an angle.

It's going to want to pull that other one up and make it as tight as possible.

And then we'll put a double header here, which will support this floor system.

♪♪ ♪♪ ♪♪ ♪♪ So, you can see here where that stack comes up.

We'll have plenty of clearance for the toilet drain... Kevin: Right.

Zack: For our laundry chute tight against that wall there, we have plenty of room.

If we have to do a trunk line, we have room there.

And then we've got all this space here for the drain for the bathtub and the overfill.

Kevin: Beautiful.

And hopefully the plumbers or the HVAC guys don't have to notch anything.

Zack: Fingers crossed on that one.

Kevin: Okay, that's a good -- Tom: Hey, glad to see you guys got rid of those old joists that were notched by the plumbers and destroyed.

But what a difference.

It's nice and straight and strong.

And I like the way you framed it here for the plumbing.

This looks great.

Kevin: Yes.

And you brought some joist hangers for us, as well.

Tom: I brought some hangers for you.

Kevin: Alright.

Zack: Excellent.

Kevin: So, good work today.

What have we got coming up next week?

Zack: Next week, I think we'll have all the backfilling in, the drainage complete that we worked on earlier, and then probably have the addition partially framed and be ready to wrap that up.

Kevin: Very nice.

Tom: So maybe we'll do some work on the second floor.

Zack: I hope so.

Kevin: Alright.

Tom: Sounds like a plan.

Kevin: So, that's it for us here in New Jersey, in Ridgewood.

So until next time, I'm Kevin O'Connor.

Zack: I'm Zack Dettmore.

Tom: And I'm Tom Silva.

Kevin: For "This Old House."

Tom: Alright, so, you guys got hanger nails, I hope?

Kevin: Yep.

Kevin: Next time on "This Old House"...

So, Colonial Revival -- tell me about it.

Woman: When we talk about Colonial Revival, we're talking about the Colonial period and the two architectural styles that we're reviving here are Federal and Georgian.

Zack: I'll use this beam saw to cut all our studs at once.

It'll just make it more consistent.

We'll have less cumulative error.

Two, three.

♪♪ All right.

Kevin: That's next time.