This Old House

Tom

Today on "This Old House," can you cantilever a rafter? Well, I'll show you how.

Kevin

Haven't you shown us a magical vent that allowed the air to go one way but not the other?

Richard

Yeah, it's an air-admittance device. Looks like this, and it's a one-way device.

Kevin

What happened to all this plumbing here?

Richard

I've never seen anything like this before.

Roger

There's already rot going on in that trunk.

Kevin

So what have you found up here?

Tom

Well, a bit of a surprise.

Richard

It's really the classic plumber's lament.

Kevin

Nice!

Norm

See this main roof form? We're just gonna pull that forward so it's even where this existing deck is.

Kevin

Definitely says mid-century modern.

Tom

The money's in the detail.

Richard

That is beautiful.

Kevin

Hi, there. I'm Kevin O'Connor, and welcome back to "This Old House" here in Brookline, Massachusetts, where we are working on this 1957 mid-century modern. Little more than halfway done, and, uh, we've got two additions on this house -- one on the far side of the house, and one right here on the close side of the house, and the last thing that we need to do before we can button it all up and start our interior finishes is to get this last bit of roof in, Tommy. And so, over what's gonna be the new living room, we got to finish the roof.

Tom

Right. This roof got a pretty funky system here.

Kevin

So, this is the sort of outside wall of the house, and this is a wall of glass, which explains all the steel.

Tom

Right, right. And that steel's got to carry a pretty heavy load. I mean, if you look at the rafters down here, they all run that way, parallel to this wall, until you get to that beam right there. Then they transition 90 degrees, and they come out, so they cantilever. So we have a rafter right here.

Kevin

What do you guys call this, an I-joist?

Tom

This is an I-joist. It's an engineered piece of rafter.

Kevin

Yep.

Tom

So, if you look at this, it has a top and a bottom and a center web.

Yep. Tom

Okay.

Kevin

That's your I-beam right there.

Tom

Right, and that web is -- the job of that web is to hold these two together. The higher the web, the longer and straighter,

the stronger the span will be. Kevin

Yes.

Tom

Okay? So now, if we take these and we support them into the hangers on that wall right there...

Kevin

Yep.

Tom

...and drop it down, spanning on this wall, and bring it out, we're now cantilevering the rafters, which gives us the overhang that we need for the porch down below.

Kevin

We're gonna step out of those glass doors onto an open porch. This is our protection from the weather.

Tom

Now, these webs, as I said, is meant to hold the top and the bottom apart, but it doesn't have a lot of force down on a point load, and the point load would be right here on the wall.

Kevin

Okay.

Tom

So think of the weight pushing down there and the weight pushing down here could crush this and damage it.

Kevin

Ah. So I'm looking at a blocking there, and I'm looking at blocking right here. That's to reinforce it at those point loads?

Tom

Right, I call it a crush block, and the block down at the end is a nailing block for our hangers.

Kevin

Oh, I see.

Tom

Another thing you want to notice is, you see the hangers that we have right there?

Kevin

I do.

Tom

Those hangers are there to hold the rafter from dropping down.

Kevin

That's kind of the way we always put them.

Tom

But we have a cantilever right here, so when there's weight on the roof, this fulcrum right here, the center of it, acts like a see-saw.

Kevin

Oh,

interesting. Tom

All right.

Kevin

So you're saying it could pop up out of that hanger?

Tom

Right. So what we do is we put a hanger that carries the load down, and we put a second hanger on top to stop the force from going up.

Kevin

Very clever. Let's get them in.

Tom

All right.

Kevin

The big bank of windows right here in the kitchen, well, they look great, but they've been causing us all sorts of trouble. There is a large gas range right here, and that has to be vented, so you're gonna have the range vent right here, but the vent pipe has to be exposed. We've also had to figure out where to put all the outlets that code requires to have all along this countertop, and, obviously, going through a window doesn't work, and now, Richard, the windows are causing us plumbing problems, too.

Richard

Right. Sink wants to go right here. Now, normally, on any kitchen sink, on any appliance, you might have the drain inside the wall -- here's the trap underneath the sink...

Yep. Richard

...and then the vent has to come above and run underneath but work its way up through the building and tie back into the vent systems.

Kevin

So it's clearly not gonna in front of the windows.

Richard

There's no spot here, Kevin. There's nowhere. It's all windows, it's all structure, right? So, if the sink was maybe at the end down here, I would contemplate actually maybe coming up and drilling through the studs, but look at this. There's a solid beam here. We can't go through this, and there's no wall here.

Kevin

Right. And coming all the way this way?

Richard

I would never go through all that structure and drill through it.

Kevin

I don't know. You've cut a couple -- No, you're right. But haven't you shown us a magical vent that allowed the air to go one way but not the other?

Richard

Yeah, it's an air-admittance device. Looks like this, and it's a one-way device. It would let air come in, but it wouldn't let it go out, okay. But this would be sitting inside the wall right here.

Kevin

Boy, that seems like the perfect application for that.

Richard

You'd think, but it's actually not approved in Massachusetts and many other states because it's relying on a mechanical device to have proper venting, and it it ever failed, then you'd have live sewer gas coming into the cabinet, so it's not approved in many places.

Kevin

So, if we can't use that, what do we use?

Richard

Well, we're gonna borrow from the technique that's always been approved with local approval by the inspector -- a thing called a bow vent. If we had the sink on an island, we'd have the same issue, right? We got no place to run the vent, so they've allowed a thing called a bow vent, and so this is the beginnings of it right here. So now this will be underneath the sink, and here's the drain going this way.

Kevin

Right. So, when you say this way, is this beneath the floor now?

Richard

Yeah, there's a -- there's a -- The floor is right here, and this is -- But now you come down here. So, at this point, everything above here goes up to just underneath the countertop, and it works its way down, and this is now a vent. But if we just ran it like this down under the floor and then ran it up through the building, it would be a place where if there was ever a stoppage, the water could back up over this point, and now it can come down here and be trapped down here, and it would trap the vent from not working anymore.

Kevin

So if a vent is filled with water, it's ineffective.

Richard

That's right, so the most important part of this piping technique is to do this. This goes here, this goes there, and then bring that other one in. This is the proper piping technique so now if there was ever a stoppage and the water came here, it would continue down. This is our vent, but it would have a relief drain right here so that it would always stay clear.

Kevin

So overflow water could go here.

Richard

Absolutely, and then you'd always have this vent right here. So now this will be below the floor. Now, once we get below the floor, I can pretty much go anywhere I want horizontally with pitch, so we'll go down here. It turns that there's no place to go up right here, so we're gonna turn again and now go up through this petition and tie back into the vent system.

Kevin

So a long way to go, but with vents, that's okay. As long as we end up through the roof, we're all right.

Richard

And they have to be properly sized.

Kevin

Good. All right, well, let's hope this is the last time the windows cause us trouble.

Richard

These windows are lovely, but they're really a pain.

Kevin

Thank you,

Richard. Richard

All right.

Kevin

Our original house has got vertical wood siding on it, and the local preservation society says we have to keep it, so we will, and for the additions, we will match it. Now, the original is probably redwood or cedar, and this is what we're gonna use for the addition. It's 1x6 cedar, it's got a V-groove, and it's all gonna be primed on all six sides before we put it up. Hey, Tommy. Hey, Erick.

Tom

Hey, Kevin, how are you?

Kevin

Hey. So, Erick, have you done any siding in your past?

Erick

Uh, not a whole lot, and not wood, so this will be fun.

Kevin

All right, I know you have, Tommy.

Tom

You might say that.

Kevin

Yep, so, we're gonna match what's on the front

of the house with the cedar. Tom

Right.

Kevin

Although you're gonna run it in a couple different directions.

Tom

Well, we have to continually match the vertical siding on the old section of the house -- this part with the old boards, the 1x8 boards. When you see the new walls here, this is all gonna be horizontally done.

Kevin

Right. Boy, if that doesn't show the difference between old and new, right? I mean, you've got the plywood that's kind of waterproof, and then you've got the old sheathing system right here.

Tom

Right. Now, this old sheathing system -- look at all the gaps between the boards, and that's all from expansion and contraction over time. When these boards were put on, they were put on wet, and they were hand-nailed. Over time, they dry out, they shrink,

now we have a lot of gaps. Kevin

I-I mean, some of those are half an inch thick, right?

Tom

Oh, yeah.

Kevin

Those were tight when they went up, right?

Tom

Absolutely, yeah. Now, you'll also notice -- you can see these nails -- all of these nail heads are actually loose now because over time, as the board expands and contracts, it pulls the nail out, the board dries, and then the board swells and pulls it out a little farther, so we need to tighten up all these nails, so we're gonna bang them in by hand and then add more. What we want to do is we want to put these boards back tight to the structure because it adds integrity to the structure.

Kevin

Looks like a perfect job for you, Erick.

Erick

Yeah.

Tom

So, Erick, you nail off those by hand, bang them in, and let's add -- let's add some more nails with it. Now, years ago, we would cover these walls with felt paper, tar paper.

Erick

Yeah, I remember taking it off when I was taking off the oldest paper.

Tom

Right, and the paper that was on it -- this right here. This is a 15-pound felt paper. Sometimes we would even use a 30-pound felt paper. It even better, but it keeps the water intrusion from getting to the building, but it also allowed the building to breathe, but we didn't use a lot of insulation there. This product right here will keep the water from getting to the building, but it's breathable, so those vapors from inside can come through the siding. It pretty much acts like this right here.

Kevin

So instead of an impregnated coating, we just have it in a sheet 'cause we're doing a retrofit.

Tom

Exactly. So now we can just take this, and we're gonna put it up on the wall. Wrap it around this corner like this, and I want to bring it down so it goes down to the foundation, because, eventually, we're gonna have to seal it to the foundation with a compatible caulking. Get it on here, and we just staple it. Get right here. All right, so now our walls are protected just about the same way. When you put the siding up, and you put it flat against the wall like that, you always have to worry about the risk of water collecting behind the two, and if we put the siding tight here, it can't dry out, all right? That's why we're gonna back-prime it, but the other thing we're gonna do is we're gonna put this matrix system right here on top of it. Then, when the board goes over it, it keeps it off the wall so the back of the back of the siding and the wall can dry out and water can run down.

Kevin

And we'll put the matrix on the old as well as the new?

Tom

Absolutely. All right, we're gonna start over here in the corner right here, and I've got a mark on the foundation to keep the bottom. Right on that mark. Got it there, Erick?

Erick

Yep, right here.

Tom

Okay, so I'll staple that, and bring it in tight to the corner. And up, even -- that's right. Yeah, let me get this where it goes here first.

Nail gun firing

Kevin

You want to wrap the corner or you want me to cut it?

Tom

No, we'll wrap it.

Kevin

So, Tommy, we -- same material that we use when we've done cedar shingling, as well.

Tom

Absolutely. We've used it on all kinds of siding.

Kevin

I got to get this nail out of here. Hang on.

Tom

All right, that's it for the first row. Let's get the second row going.

Richard

The principal source of heating in this house will be radiant floor heating in every single horizontal surface in the building, but we still need air-conditioning and dehumidification, and this building has got zero space for mechanical. It has no attic, and it has no real usable basement. The basement is actually gonna be used as an exercise room. So we fought for mechanical room space. We got a little bit at one end to put an air handler for the kitchen/living room, and we have another space right here for another air handler. Air handler's pretty straightforward. It has a blower right here that'll push out through into a small duct system. Down here there's a refrigerant coil that'll actually cool the air, and that's gonna connect to a condenser up on the roof. Now, the condenser's up there because we really don't have a lot of space around this relatively small footprint of a lot we've got here. Now, that condenser can also act as a heat pump as a backup or a boost feature if we want to. Now, to get started, we're gonna get this air handler mounted right here on the wall. Matt Furrier and his crew is helping with the installation on this job. At the base, there's a filter box that'll be the return-air portion. The air handler will then mount to the wall. Now, you can see on this side our refrigeration connection will go out to our condenser, and down here is a condensate drain. Anytime you air-condition, you're gonna make water, and you have to get rid of the condensate, so there will be a drain right here. It'll go down to a little pump that will pump it out. On this lower level, we're gonna end up with two zones -- one for the lower bedrooms, one for the upper bedrooms. So we'll have a T right here, and it'll go to two branches with two motorized dampers. This is a zone damper that'll close off for each zone. I'll give you that, Peter. With a conventional ducted system, the ductwork always starts really big at the air handler, and then it gets smaller and smaller and smaller as rooms get taken off of the main trunk, but with a small duct's high-velocity system, it's one-size supply trunk. This size is just six-inch round insulated duct, and we had to fight to even find this spot right here. We have a spot. Because the foundation is here, we were gonna lose it, and there weren't many places to lose the ductwork. So, it runs right here, and this will be for this lower zone. Off of the trunk, we'll cut in the sound attenuator. This is a spun-nylon attenuator to knock down any velocity noise because the air in these type of systems moves faster, but, properly installed, it'll be quiet. It'll plug into here, and then the outlets come into the room, and you just need to be sure that the outlets don't blow on people. They have to just be in corners where they won't blow on people. So that's for the supply. Now, on the return side, the return has a filter from the factory -- has a filter like this, and it's supposed to connect to a flexible duct like this. Well, there's absolutely zero space for this. Right above us is a bathroom. We can't go here. We really have no place to run this duct, so what we did was to change it to individual smaller returns. So you can see right here, this is an oval, and the oval will be able to fit inside of a 2-by-4 wall and be padded out a little bit, and then right up above us, this is what the return boot will look like. It'll be a much smaller grill. There will be three of them that run down here inside this wall, and what they do is they come right down and come out through here and tie into the bottom of this return box. There's one filter for the whole system but three individual returns. This house is not easy. Up here on this level are our bedrooms. It has its own zone. Now, right below us is that mechanical closet where the air handler is, and above it is the bathroom. We needed to find a way to get a trunk up to this level. We looked around. There wasn't many places to do it except, fortunately, right here is a closet, so we could lose this trunk in the back side of the closet, and once we did that, it freed us up to supply that bedroom, the bathroom, and this part of this bedroom, but, out here, lookit. There's a wide-open petition. There's no real place to run it. We actually can't run the attenuator up inside this insulated ceiling 'cause that would void the insulation, so what we did is we ran them here -- the attenuators -- here with a slotted outlet that'll sit on the high side wall. The reason for that is, if you have a conventional outlet, you can't really run it inside of a 2x4 wall 'cause it would kink it and constrict it too much, so they make these slotted outlets, which are perfect to fit inside of a 2x4 wall. They also make them, actually, in a straight outlet here, and we've used these to be in the kickplate on a kitchen cabinet so it comes out low out of sight. There's really not too many houses we can't fit it in. If we did it here, we can do it just about anywhere.

Kevin

There is an entryway off of the patio right here, and even though we've got these large roof overhangs and we're gonna have gutters to catch the rainwater -- Tommy,

if you'll clip me in... Tom

Oh, yeah.

Kevin

...and it's not just the rainwater that we have to worry about up here.

Tom

No, it's really in the wintertime. You get all that snow, and that snow could turn to ice, and the ice can actually slide off the roof, and that's not good on that entryway down there.

Kevin

Right, that could really hurt somebody.

Tom

Right.

Kevin

So, the entryway's just here. We're not worried about the other spots.

Tom

No, that can slide off, and it will slide off, but right here we have to put a snow fence or a snow guide right here to hold it in place while it melts.

Kevin

So you've got, one, two, three -- three what? What did you put down there?

Tom

Three steel brackets right here. This is my last one I have to do.

Kevin

Oh, look at that.

Tom

And this bracket made of stainless with bolts in it, and we're gonna fasten it to the roof. Now, it's important that these get screwed into structure below, so I have to know where these are going so we can put solid blocking underneath so we can screw into it.

Kevin

All right, well, I can see that you've got that marked off, so that is already done. And you're putting them into the roof?

Tom

We're gonna put them into the roof, but the first thing we're gonna do is put this gonna put this mastic down here on the roof.

Kevin

So this is an adhesive, as opposed to a sealant, or both?

Tom

It's an adhesive. It is waterproofing. Everything. So it's gonna seal right down under there so no water will get underneath this.

Kevin

Gotcha.

Tom

It's just a line -- another line of defense. Slide that in there, and we put these screws in here. We alway-- We have to also worry about holding it down tight. We have to worry about shear strength, too, so you want to make sure you use the right kind of screw.

Kevin

It, uh -- It pains me to see you put a screw through our newly rubbered waterproof roof.

Tom

I know it. I know it. But we'll be able to seal that right up by putting a piece of rubber right over it.

I'll show you how. Kevin

Now, you can definitely tell you got structure underneath there.

Tom

Oh, yeah. If you didn't have it, the screw would just spin out, and then you got to worry about it ripping off the roof. You don't want it pulling the brackets out of the roof. Okay, so now that we have that screwed down, the next thing you got to do is just wipe off any of this dirt, clean the area nice, and I'm gonna take this cement, and we're gonna go right around the bracket and over the bracket, too, with this contact cement. So we want to put it right on the roof. Okay, so we just coat that like that. We got to give it a few minutes for it to get tacky, and then we'll take another piece of uncured rubber and lay it right over it. And once I lay this down, I don't get a second chance, so I want to make sure it's right. Put it down there, and I'm slowly gonna work my way up the roof putting it in, trying to lay it flat as I can 'til I get almost to those bolts sticking out. Take my knife. I'm gonna put a slice in it here. Slice in this one. Now I should be able to stretch that right over those nuts and bolts. Push it down. Now I got to slowly work my way back.

Kevin

Now I feel a lot better about those screw that you just put through our roof.

Tom

Yeah, I mean, this is definitely sealing it right up nice and tight. And I want to push everything down. Start in the middle and work my way out. All right, so now we're gonna put the top plate on, but just before that, I'm gonna put a little bit of this around the crack or slice that I made. Now we'll take that bracket.

Kevin

It's another piece of aluminum.

Tom

Yeah, another piece of aluminum, all drilled, lines up with the bolts sticking through our bracket on the roof. So now we're gonna put this washer on first, and that little rubber part of the washer goes down first.

Kevin

That's interesting. So even the washer has got a little gasket there.

Tom

Yeah, it'll seal it everywhere. Take this one. Screw this one down. Okay, now we'll put a nut on there. Okay. All right, so now what I'm gonna do is take this black lap sealant. Gonna go around the bracket.

Kevin

It's like the whole system was developed by a guy who had to go back up on the roof and chase a leak.

Tom

Probably right.

Kevin

And he said, "Never again."

Tom

All right, now our brackets are in, and we're gonna install pipes through the holes to hold the snow back, and these pipes are aluminum, and they come in different materials. You can get them in bronze, copper, whatever you want. These are aluminum. All right, now I'll get the coupling on first. Now slide that pipe in. Okay, wait a minute. Make sure you're in tight. Okay, now turn that pipe.

Kevin

Oh, yeah, you can feel it tighten right up.

Tom

Yep. Just make it snug. Good. So, now we have these stops right here that will go in against the bracket on the top and the bottom and a little Allen screw that will tighten onto the pipe, and that'll keep the pipes from sliding left and right. So, that's all it takes to keep the snow from sliding off the roof in the winter.

Kevin

They are gonna appreciate that when the bad weather comes.

Tom

Oh, yeah. And now we have these little end caps right here that will go on the end of the pipe, close them up so it'll keep the bees out.

Kevin

All right. I'm Kevin O'Connor.

I'm Tom Silva. Kevin

For "This Old House." All right, so just one?

Tom

Just one, that's all.

Kevin

Next time on "This Old House"...

Tom

We'll show you how we turn the corner for the siding on our modern home. Tap it down to make the tongue-and-groove joint nice and tight.

Scott

Yeah, it is in tough shape, but when in Rome, we want to be Romans.

Kevin

It's time to fix a puddingstone wall. And, Tommy, it was part of our 40th anniversary. Fond memories of the Cambridge project?

Tom

Fond memories -- this was a great project.