I plan on building a 2nd story deck that is supported by brick columns.
I would like to support the free end of the deck with 3 square brick
columns that extend through the deck floor to provide attachments for
railing. The height of the deck floor from the ground will be 11 feet.
I have a few questions:
1. How large should the columns be?
2. Should there be an additional support structure inside of the
columns? (concrete blocks, poured concrete, wood column, etc)
3. How would the deck be attached to the columns?
4. How would the deck be attached to the house? I can use posts that
are placed next to the house but since the house is under construction
and has not been bricked yet, I was hoping there was a way to attached
something to the structure before the brick is layed that will support
Thanks for your input.
In seismic zones the city will want civil or structural
engineering on the columns. If I were going to boot leg it
in Id put blocks down the center with 4 1/2" rebars then
pour the centers then brick around the outside. Id photo
graph the entire set up so if the city comes out later you
have a chance the inspector wont make you tear it out...Id
also leave the top caps removeble do the rebar install can be
Best would be to get a city permit maybe you can get by
without hiring a civil or structural engr.
attachment to the house is usually by a stringer attached to
the side wall but that needs design work to insure is flashed
properly etc. and will be compatible with the rest of the wall
You sound a little green to be doing this without a contractor
to advise you...pay the home builder to advise you..that
Soil conditions are an issue also..its not totally simple.
You dont want those heavy columns sinking over time etc.
it needs some quality design work from someone that knows the
site conditions and the local building dept
I concur with Phil's assessment that engineering will be required if you
plan to get a permit (a wise choice). As for DIY, the (4) # 4 are
probably okay, but if you are in a medium or high seismic risk zone you
will need to add ties wrapping around the verticals. The size and spacing
if the ties is partially dependent on the column dimensions.
Bob Morrison, PE, SE
R L Morrison Engineering Co
Thats a lot of questions.... I'll number the answers to match.
1. The width of the columns is aesthetic. However, your brick mason will
appreciate it if you make them work out to even brickwork. There is a
give/take issue here too. The columns are pretty tall. If you go too
small, they may look "spindly" from the rear. Since they will extend to the
rail height, they will be visible on the deck. Wide columns will look (and
be) very big when viewed from the deck.
2. I usually brick around a concrete block column. The block helps keep
things square and add some solid structure to the center.
3. The attachement of the deck to the columns is the tricky part. I prefer
to have the mason leave an opening where the deck band can be inserted into
the column so that it bears on masonry. This typically leaves a gap but we
cover it by running a trim board (treated) around the band. Alternatively,
you could "hang" the deck from the columns. This would require drilling and
bolting the band to the columns and then hanging the joists on that band.
The downside is that there isn't much material for attachment on a column
and it could be somewhat brittle.
4. The deck should be attached to the house with lag bolts. The deck will
be built after the brickwork is done. The deck ledger (band) will be bolted
through the brick (and into the wooded structure of the floor system). No
posts will be needed against the house.
FYI, it seems like a simple undertaking, but this is a detail that adds a
great deal of complexity to a typically simple process. Don't be surprised
by the cost of this upgrade.
If I may, note that quite a few decks have pulled away from dwellings due to
the use of lag bolts with fatal results, and as such, lag bolts are now
illegal in many areas for attaching decks to the main structure. I usually
install full thread 1/2" carriage bolts w/nuts flat washers on four-foot
centers (check local code) from the inside of the floor joist band outwards
long enough to reach through the brick and deck band, and then have the
masons brick around the bolts. Much easier than drilling through the brick
after the fact.
I agree with the others, given your level of expertise, a few dollars spent
for proper engineering and oversight would be well spent in this case. A
deck that high off the ground with a party of imbibed guests jumping around
is a recipe for disaster if it fails. :)
Furthermore, being this is new construction, make damn certain that you
don't pour the footings on fresh backfill. Dig/drill down to solid/virgin
soil as needed. Important!
Have you considered a suspended poured slab over a bricked wall with large
open arches underneath? No wood to treat and not much more expensive than
an all wood deck with an upscale appearance that will last the life of the
house. Just a thought.
Brick columns that could support your deck would be quite large. Most of the
skinny and elegent brick coumns you see in modern construction are merely a
brick veneer on the actual support structure. Burying wood in masonry is
usually a bad idea- talk to your builder, this shouldn't be a real big deal
for him to add to the plans- concrete footers (with brick ledges) for a
bolted and welded steel post and I-beam setup to hold the deck. (You paint
it with a rust-proof paint before the brick goes on.) How it attaches to the
house will depend on how it is structured, local soil conditions, etc.
Generally, the deck structure will tie to a ledger board or well-supported
'pockets' in the house framework, but if the deck is big enough, you may
want it to be free-standing with a flexible cosmetic connection. If a bad
frost or high wind heaves the deck a little, you don't want it to break the
house, or pop bricks loose at the seam. From your description, the deck
sounds like it will be a fancy attached carport, even if you don't actually
pave under it. Don't forget to make provisions for drainage of the upper
deck surface, especially at the seam with the house. Usually a good idea to
hold the deck a couple inches below the threshold level of the doors into
the upper floor. Hope you have a good contractor- doing this right is
outside the skill set of most mass builders.
You've had some good replies so far, Re structural design and permit issues.
But I note you gave no length and breadth spec.
But, to 'guesstimate', if the decks in a non-seismic area and not much wider
than 10', you should at least use a "1 1/2 brick" (13"x13") square brick
collumns @ +/-10' centers, with steel or RC structural core *essential* [eg:
well-compacted concrete (1cement/3sand/3stone) fill and min 2 x rebar -
right down into the footing (min 3'3" square)] for this loading at this
height. I can't advise
on attaching to wall-framing, but the (hardwood) deck bearers can be built
into the brickwork [ full brick width ] with those ends pre-treated with
waterproofer/ plastic wrapping. Make them min. one-size-bigger-than-minimum
timber sections for your spans, in case there's ever going to be a bunch of
people dancing around on that deck!
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