DIYbanter - View Single Post - Hammer drills

-MIKE-

On 8/14/17 1:07 PM, wrote:
On Monday, August 14, 2017 at 11:51:24 AM UTC-5, -MIKE- wrote:
On 8/14/17 10:01 AM, tdacon wrote:
I'll take Mike's word on sealing the ledger. You're talking to
long-time classic wooden boat guys here - my friend is an
English-trained shipwright, and I've owned a classic wooden sloop
for over forty years. So we know caulk. Fresh water leaks are the
death of a wooden boat.

That was me. Cracks, seams, gaps... all need waterproofing of some
type when outside unless it is fencing. Part of my company is
waterproofing, so I use a LOT of elastomeric caulks to seal
dissimilar materials to one another.

My advice was to not use a ledger at all. I advise to use
separate footings/posts and not have the deck physically attached
to the house at all. If digging too close to the house is a
deterring issue, then you could always put the posts 3 or 4 feet
away from the house and cantilever the joists over the beam, to the
house.

I know NOTHING about building in Vermont, but I think styles of
building decks are probably pretty regional. For example, the county
I live in is almost 1300 square miles (!!) so that comprises a lot of
area. At the southern end of the county there is a lot of black
dirt, and pretty stable substrate. North of that is a wide band of
very plastic soil that moves tremendously, keeping at least three
hundred slab/foundation repair guys constantly busy. It is no
uncommon for a house to have large sections break off and move away
from the larger portion of the house. When I revamped my parent's
house for sale a few years ago, they had a 1" separation of the back
third of their house from the slab!

North of the city/county, topsoil barely covers rock. To make VA/FHA
requirements on new homes, they truck in soil from the south end of
the county to be able to meet the minimum depth requirements. Slabs
are poured on top of cleaned bedrock if a engineer can determine the
proper type and thickness of the underlying rock. Houses built on
those never, ever, move.

So we attach our decks to the houses for two different reasons.
First, the deck that isn't attached to the house can simply wander
off into the yard over a period of years. And second, if the house
is completely stable, why not? We get torrential rain here, followed
by long periods of dryness, then drought. We have no snow melts, no
ice build ups, nothing that would keep wood soaked for long periods.

That being said, I don't like the ledger detail. It is commonly
used, but to me, especially considering today's inferior material
quality it is a bad one. I won't use a wood ledger unless people put
me in that position by wanting the lowest price on the job. I
learned this while doing commercial work.

I go to one of the local welding shops and have them cut a piece of
3" angle for me to the length I need. This is usually about 16 feet
or so, and costs me about $60. Then I have them punch 1/2" holes
every 16". It always winds up with the total cost being about $125
for the piece, so I am guessing I am paying about $4 a hole.

I put the ledge up so it looks like a "7", so that when it is mounted
the anchors are shielded from water. After the holes are marked, I
put a coat of enamel on the angle while the anchor holes (3/8") are
being drilled. I mount the angle and set the joists on top of it,
putting blocking in between the joists. I don't nail the joists to
the anything to attach, like you description, they sit on the angle,
but cantilever from the last structural beam. I do tack in the
bridge block, but that's it.

I have been using that detail for 30 years, and as I said it is
modified from a detail I used when pouring tilt panels and attached
bar joists to standing walls. Never had that detail fail, but for
some reason, I am the only guy I know that uses it. I see those damn
wood ledgers up everywhere, and the structure/joists toe nailed into
it. Decks built that way will fail, and some do in just a few years.
I can see how that would be a worthless detail is you had snow or ice
on top of it.

Robert

IMO, if the soil it too unstable to built upon, then nothing should be
built upon it. :-)
I grew up in the snow belt on Lake Erie, and our frost line was well
below 3 feet, so I am familiar with the "crawl" effect of freeze & thaw
cycles. even in cases where footers are below 4ft deep, if the footing
isn't smooth, the ice can grab it and heave it upwards.

In regards to this, I find this as even more reason to not attach the
deck to the house. If you do end up with a deck crawl, it's going to
try to pull away from the house, causing a failure somewhere in the chain.

There are ways to anchor footings to bedrock when there isn't enough
topsoil, but I've never had to deal with that. But it's important
around here where the bedrock is less than a foot deep in many places
and there are lots and lots of hillside building.

We almost bought a home on a hillside with a gorgeous hilltop view, but
it had serious foundation issues. It was basically slipping down the
hill inch my inch every year. They had spent over $30k to have pilings
installed and we had the option of paying several thousands to "extend
the warranty" which had already been extended about 3x with 2 extra
piling installation jobs. To me the extended warranty was simply a down
payment on future piling installations. I don't think that house will
be there 20 years from now. Or if it is, it won't have that gorgeous
"hilltop" view anymore. :-)

I like your iron ledger technique. You should send that in to Fine
Homebuilding.

--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
www.mikedrums.com