How to Install and Flash a Deck Ledger, Start to Finish

Sharing buttons:


so we're doing a ledger and the most

important part of installing ledger

right is making sure that it's long

lasting it can support the deck for the

duration of the decks life so in order

to prevent any problems with water

getting into the wall that can rot out

the rim joist to the house and cause the

whole deck to pull away we're gonna make

sure we got a good flashing system and

that starts with some peel-and-stick

membranes some self adhered membrane

that goes against the wall what you see

here this gray part down here is

indicating a foundation wall and then

we've got our wall that we're going to

be attaching everything to I've already

established my grades for this deck I've

already got my footing locations a level

line over here some marks that are my

top of the ledger board and I've snapped

a chalk line above that four to six

inches and that's gonna be where I'm

gonna put that self adhered membrane

against the wall here's a piece of

membrane we're going to be putting on

the wall it's 18 inches wide and it's

gonna bridge from the top of that line

down to at least three or four inches

below the bottom of the ledger board now

I've scored the release paper on the

back of the ceiling stick because I want

to be able to separate in two separate

pieces that way later on when the siding

goes on the wall if we're working on

upper portion of the house we can tuck

the siding underneath that

peel-and-stick membrane so water gets

shed out so now we're ready to put the

membrane on the wall now it's not very

warm in the studio here so this isn't

going to stick readily to the wall so

I'm gonna use a hammer attacker stapler

to put it on I got the line here where

my ledger is eventually gonna go I want

to make sure I'm past that by four to

six inches I'll pull that over there

stick it to the wall just give it a tack

now you just stay a little bit ahead of

me and I'm gonna pull the membrane

release paper off and if you're not

perfect on the line that's fine really

we want to just be pretty close so we


a bunch of wrinkles and now that we got

the membrane on the wall we could snap a

chalk line and then we can start putting

the ledger on so we're going with that

bottom line right there got it

I'm gonna adjust it to the line I've got

over here

you're Endel automatically go where it's

supposed to let me start first okay now

you can just spin them all in just make

sure you don't sink them

so here we got a mock-up of the model

wall that we've been working from and

the screws we just put in so we use

structural screws for this detail here

you can see we got the ledger board we

got the wall sheathing await the rim

joists to the house now first off when

we were planning this I had to make sure

that the screws are going to be long

enough to go all the way through that

sandwich some cases you got a thicker

sheathing you might have a space there

you're going to need longer screws when

the screws penetrate through want to

make sure that there at least the tip

sticking through they don't have to be

through an inch or anything like that

just the tip sticking through so in this

case we got like three and a half or

three and three-quarter inch screws

screws come with different head profiles

some are flush washer type screw heads

others have hex head screw heads in

either case what we want to do when

we're laying out the screw pattern on

the wall or on the ledger board want to

make sure that we avoid any joists or

the flanges of the hangers that are

supporting those joists so we get that

layout for the pattern from the screws

from the manufacturers installation

instructions and based on the span of

the joists from the ledger board out to

the caring beam based on the load that's

going to be on the deck as well as what

the rim joist material is that's behind

the wall those are all going to play

into the spacing we read that right off

the table and then we got our spacing

let's say in this instance we got

seventeen inches apart now obviously if

we do our joist at 16 inches apart and

our screw spacing at 17 at some point

we're gonna end up with a conflict where

a screw is going to end up landing

either where a joist is or where the

flange of a hanger is going to go in

that case the manufacturer as well as

the code allow us to smooth that one

screw off position by up to three inches

left or right that way we can avoid a

conflict and that's particularly the

case when we're using the hex head

screws with the washer head type screws

they're not going to be such a problem

because they're a fairly flat profile

and you often the joists they'll be able

to clear right over that if we set those

flush no matter which ledger attachment

system you end up using you're still

going to want to continue the continuity

of our ledger flashing system with an

extra piece of self adhering em brain

it's gonna go on top of the ledger so

here I've already scored the release

sheet on the back about two inches up

and that makes it easier to install

because I can peel off the bottom piece

or the top piece of the release paper

separately from the other piece which

will make installation less prone to

sticking where it doesn't belong so I'm

going to overhang this a little bit over

the left side by about an inch and I

usually just start in the middle now

you'll notice I'm working with a fairly

short piece and that's because when

you're working alone it's just a drag to

try to work with long pieces of the

sticky stuff I'm better off working with

short pieces I'm less likely to make a

mistake stick it in the wrong spot and

end up with a mess on my hands key thing

here when I'm putting this second layer

down over the top of the ledger so I

want to make sure I'm tight on that

inside corner and that way I don't end

up with a like a curved part of a bridge

in there that could get ruptured when I

put the metal flashing on once that's in

nice and snug

a little bit that goes down the face now

this could be a quarter of an inch down

it could be three inches down some

people put it all the way to the bottom

of the ledger board whatever you prefer

is fine and I just work my way down in

these wing span length pieces with an

overlap of you know roughly four inches

and if it's a hot day or a sunny day

where you're afraid of this stuff

getting stuck where you don't want it

what I recommend is pre-cut the pieces

bring a cooler to the job with you with

some ice in it and just stick it in the

ice cooler for about thirty minutes

before you're going to stick it on the

wall that'll chill it down and it won't

be as sticky that way if you end up

touching it where you don't want it

won't bond to the wall and make a mess

on you and once it warms up give it an

extra press and that'll seal everything

in now if you're in an area that doesn't

get a lot of rainfall you might be

looking at this and thinking man that's

overkill but for those of us that live

in higher rain zone areas or even if

we're not high rain zone area but when

we do get rain it comes down in torrents

the risk is if you don't do a good

flashing job that we end up getting

water that back behind the ledger board

now of course we pre flashed it with

that first piece of peel-and-stick so

this in a little bit of a way becomes

redundant but I'd really rather get this

water to flow out over the top of the

ledger than relying on my insurance

policy that we have down underneath now

the two ends I'm just going to make a

little bit of a relief cut diagonally

out from the corner about a quarter of

an inch out from where the end of the

ledger is most of these plastic surface

membranes will stretch just a little bit

and gives us a little extra protection

right there then I can wrap around the

corner go back and do the other end

just to recap a little bit on this just

to point out a couple different benefits

of doing the system this way if this is

my foundation down below here and I'm

putting the membrane on over the

foundation I'm gonna want to cover this

up even if this is a low deck to the


you know this in sunlight is not going

to get to it I'd still rather cover it

up just to keep any critters from

getting back there and messing with it

or if it's up high enough where you

could see it then you're definitely

gonna want to trim board so that could

be a one by something that's just gonna

fasten on the lower part of the building

where you still have some wood and that

way it covers over the foundation and it

also covers over the piece of

self-adhering now if this was a deck

that was up say second-story on a house

this becomes extra valuable because as

you're bringing your cladding up if it's

any type of lap siding this could be

vinyl siding it could be wood clapboard

it could be any sort of engineer type of

siding the next-to-the-last course when

you install that nail it in place but

make sure you tuck it underneath the

peel and stick the reason why I've left

that release paper on there was so that

I could lift this up so now I can lift

this up tuck that clapboard under there

then I can put the final piece of

clapboard on that way any water that

does get back there gets drained out

onto the surface of that peel-and-stick

material doesn't get kicked out on top

of the house wrap up of both here it's

going to end up getting kicked out on

top of the surface of the siding and

that way it's traveling in an area

that's a lot more safe than behind this

up now at the end over here the benefit

of leaving this one piece that we backed

up our ledger board with extra an extra

four or five inches long is because

that's a vulnerable spot in any detail

where you've got a butt joint between

the siding and the ledger board if I

just had house wrap back there yeah

hopefully the house wrap would be free

of holes and the water would get back

there and then it would drain down

behind the house wrap without doing any

harm well by having that peeling stick

or a little longer now when I tuck this

piece of siding underneath and I got

that butt joint there if any water gets

in that butt joint now it gets kicked

out onto the top of that siding or it

can do no harm

face of the wall don't worry about

putting another piece of clapboard or

siding over the top that you're gonna

trap water back there if you're worried

about that just take a couple of

toothpicks slip those underneath that'll

leave enough space for weeping of the

water between those laps now eventually

what you'll see is we'll put a metal

flashing over the top of this we can't

leave these feel and stick materials on

the wall exposed to daylight and one of

the things most contractors don't

realize is that once we put our final

piece of deck board on the siding that

goes above that you need to have a

certain distance between the siding and

the finished piece of decking that could

be a half inch it could be up to two

inches depending on the branded type of

siding so by having that metal flashing

not only is it a good deflector of all

the water it can also be color matched

so that you don't view a strip of the

peel-and-stick which can't be exposed to

UV light and it also provides some

protection for the material that's

underneath that way you've got double

protection you got the primary metal

flashing if that gets damaged we have

the peel and stick material which will

catch any of the water that gets through

our primary flashing drain that over the

face and if any water gets through that

we got that backup sheet so triple

protected now that I got my joist

hangers in place I'm gonna put the cap

flashing on top and the reason I'm doing

it now is because the joists are going

to be coming in if I waited till after

the joists were in I'd have a hard time

getting this drop leg in the front that

goes over the front of the ledger behind

those joists so I'm dropping it in now

now that that's finished once I put the

fasteners on we'll be bringing our water

resistant barrier over the top of that

leaving our appropriate clearance space

above the top of the decking to the

bottom of the cladding and then once the

cladding goes on we've got a waterproof

ledger installation