Waterproofing slip joints in gutters?

[Mark]

I just finished replacing a gutter, and all the slip joints are
leaking to varying degrees. Any tips for getting them
watertight? I applied an appropriate (I think) caulk to
the male end of each joint prior to assembly, but apparently
it wasn't enough. Do I need to completely caulk over the
slip joint clips inside the gutter?

Thanks
-Mark

[DanG]

The only type of caulk I would use on gutter connections is butyl
rubber. The only way to install it is inside the lap, not smeared
on top.

When you say slip joints, it makes me think you are talking about
downspout pipe and fittings that are crimped on one end to slide
into another joint. If these are leaking, I would guess you
installed them backwards. The crimped end is always on the bottom
of each fitting to go inside the next piece. They should need
little or no caulk.

(top posted for your convenience)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)
dgri...@7cox.net

"Mark" <nos...@thanksanyway.org> wrote in message
news:f_qdnYXqWbE...@w-link.net...

[JR-jred]

In article <l708i1538ldf9b3v4...@4ax.com>,
mg <m...@xty.com> wrote:

> The only way is to minimize expansion and contraction. clean/scrape
> the caulking. apply gutter sealer (like Parbon) between the laps and
> double screw (not rivets) the gutters. half inch form the inside lap
> and another half to an inch from that screw. sides and bottom. apply
> sealer to the inside seam (it should be oozing out already) and
> screws. haven't done gutter work in 10 years. never tried this, use a
> strip of weather shield and screws. the key is to stop the expansion
> and contraction. it will last for years. works on miter too.

Weather shield deteriorates quickly in daylight from UV. Better to use
uncured rubber. That's what many commercial roofers use. No screws,
glue.

--
-JR
Hung like Einstein and smart as a horse
Remove NO SPAM from e-mai address to reply

[Mark]

"DanG" <dgri...@7cox.net> wrote:
>
> When you say slip joints, it makes me think you are talking about
> downspout pipe and fittings that are crimped on one end to slide into
> another joint.

No, I figured that part out. I'm talking about the aluminum gutter
systems that press together using factory-mitred corner units with
clips at each end. The straight runs press into these clips, which
does make it easier to assemble the gutters. In my limited
experience, however, these joints are rather difficult to waterproof.
Also, each clip introduces an obstruction to water passage that
will allow about 1/8" of standing water to remain upstream
of each clip. Not so good, IMHO. Also, the gutters have a
somewhat "clunky" look to them with all the seams. Finally,
it is easy to introduce a high or low spot where two sections
press together.

I canvassed the neighborhood this morning and confirmed that
none of the professional roofers in our area are using these
press-together systems. All of the gutters I inspected use
straight stock with mitred ends. This looks cleaner, and it
allows sealant to be placed between lapped joints, eliminating
the shearing of sealant in a press-fit joint.

I experimented with tin snips on a piece of scrap gutter.
I concluded that proper mitering will require a mitre saw
with a cutoff blade.

Luckily, this lesson only cost me about forty bucks and a
few hours of work.

-Mark