Hi,
How best should I attach trim over diagonal siding?
(See Background, below, for information on the siding, existing trim and house construction. Photo also attached.)
I’m re-finishing the diagonal cedar tongue-and-groove siding on our house. I’ve noticed some rotting of both the cedar siding and the (pine?) trim behind the watertable boards. The water may be getting in as rain dripping down the siding. Caulking the upper horizontal joint where the watertable board overlaps the siding would prevent this. However, the lower edge of the siding and the overlapping watertable board is only 1-3 inches above grade. (It comes down this low because that’s the transition to the concrete foundation.) So, water may also be getting in during a spring snow melt, or as rebounding rain off grade. (The ground surface is sloped away from the house, but, sometimes the accumulated snow dams melt water up against the house for a few days.) (Although the end grain of the siding is exposed, I haven’t notice any rotting there. However, I have noticed some swelling and greying of the lower edge of the particle board sheathing behind the siding.) Caulking the lower horizontal joint – and all butt joints of the watertable board – would prevent this water ingress from below. But, if any water does get in-between the siding and the trim after having caulked all the joints, there’d be no way for the water to get out. Thus, I’m not sure whether I’m better to attempt to seal the space between the water table board and siding completely or to leave the trim uncaulked to allow the water to evaporate out and allow some air flow between the trim and siding.
Also, I’d like to install trim around our windows and doors. Currently there’s none – just the narrow white edging that comes with the vinyl clad windows, and the narrow edging that came with the doors. I’d like advice on how best to install the trim to avoid promoting rot behind it.
(I’ve read some of the discussion at this forum addressing the relative merits of the various ways of arranging siding. I realize that the diagonal arrangement is inherently more likely to allow water ingress than horizontal, but, at this time I’d prefer to work with what I’ve got, ie, I’d rather not remove the siding and reinstall it horizontally.)
BACKGROUND
We have recently bought a 10 year old home in New Brunswick, near Fredericton. The house is a split entry contemporary style. It’s about 38 ft by 72 ft with the long axis running East-West. Roof is pavilion-hipped. Attached is a photo looking at the east and north sides of the house.
The north and east sides are covered with 3/4 inch thick 6 inch wide tongue and groove cedar siding installed diagonally. Six inch wide 3/4 thick boards are installed over the siding at the corners (corner boards) and horizontally along the bottom of the siding. This horizontal board (water table board?) is located one to 3 inches above grade. Grade on the east side is either asphalt driveway or interlocking brick walkway, both right up to the concrete foundation. Grade on the north side is interlocking brick walkway for 2/3 of the frontage, and mulch covered earth for the remainder.
The east side is about 38 feet long, the north side about 72 feet long. The exterior walls are about 14 feet high from grade to eaves. The eaves overhang the walls by about 16 inches. There are no gutters at the roof line.
The siding has been applied nailed directly to the sheathing, ie, no furring. Sheathing is 3/4 inch particle board.
Wall construction is nominal 2×6 on 16 inch centres.
FINISH: The siding was finished with a transparent/clear finish. Over this, a solid stain (nut brown) was applied in a horizontal band from grade to about 4 feet. The trim boards were finished with a solid stain (medium light green). Neither the siding nor the trim boards have been finished on the back side, nor on the ends. Appears that the siding was finished after being installed, and after the trim boards were installed.
Their is no caulking anywhere on the siding: between butt joints of siding; where siding butts up against window or door trim; at the joint where trim boards overlap siding.
There is no flashing at the waterboard or cornerboards.
There is no trim at the windows or doors. Windows are vinyl clad casement type. The siding butts up to the window frame; there is no additional flashing and no caulking – the end grain of the siding is visible at the window frame. The siding is almost flush with the window frame.
WEATHER: From -30C to +35C. Summer is often humid, muggy – we keep a dehumidifier running constantly throughout the summer. Can get heavy rains and strong winds, but, not hurricane strengths. Can be a challenge to find 5-7 dry dies in a row to get exterior painting/staining done. Snows can often accumulate to 3-4 ft.
[Originally attached photo was wrong – removed. See later posts for correct photo. John S.]
Edited 9/7/2004 9:57 am ET by John_S
Replies
Well, you sure did a nice and thorough job of presenting your problem. I was hoping for more replies--maybe after the hoiliday. I'll reply whil we're waiting for someone who knows what they're doing to reply. I know about enough to be dangerous.
I'd avoid caulk on any horizontal surface, except at tops of things. Like you say, once water does get in, you want it to be able to get back out. Would you consider gutters? I myself hate them, but they would prevent the water running down from the eves onto the siding and the backsplash from the ground onto the siding at the bottom of the walls. I would trim away the siding around windows, flash, starting at bottom ond working way up to over windows and apply trim. I haven't heard of flashing a watertable, but if it seems to be trapping water...You'd have to do something like cut through the siding at the top edge of the watertable, take it and the lower pieces of siding off, put a Z-profile flashing under the newly-cut ends of the siding and slip the trim and off cut pieces of siding back and slip the watertable under the flashing and nail in place. I guess whileI had the lower siding, trim and watertable off, I'd put self adhesive Ice Guard on the sheathing and probably overkill, but install a drip edge at the lowest edge.
This may hold you until someone else responds--food for thought anyway. Speaking of which, my dinner is ready! Best wishes.
Excellent written description, terrible picture ... sort of. Please download Irfanview ... it's free ... and use it to reduce the size of the picture. Anything over 100k is a killer for us old fogies witrh dial up connections. Do a search here for Irfan and read the good discussions.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
john ... the picture does nothing for me..
it looks like a sideways picture of a door trim with horizontal vinyl siding buttin it..
as for your diagonal siding problem..
diagonal siding is always a problem.. it's got to be the stupidist idea ever to come down the pike
what it amounts to is a diagonal gutter every 6 inches dumping water onto horizontal surfaces..
unless it is absolutely uncehecked and with no holes.. and terminates on a good Z-flash it HAS to leak...
seems from your description that it is NOT properly flashed.. and
i'll bet that there are numerous holes and splits that allow water to get behind it on every joint..
this water will flow behind the siding until it hits a horizontal surface, then it will soak that and keep it soaked until it can rot it's way into the interior framing..
you can keep trying to caulk it .. but if it were mine , i'd rip it off one wall at a time and reside it with something else
but hey, whadda i no ?
Mike Smith Rhode Island : Design / Build / Repair / Restore
A coupla yrs ago, I was putting an addition on house with 5/4 T&G redwood diagonal siding...it was SCREWED through the tongues with #6 x 1.5 SS screws, EVERY foot to SIP's....arrrghh.
The HO wanted to save the siding for the addition..so every screw hadda be undriven..When we saw all the damage behind the siding, he realized that me telling him it was STOOPID to re-do at a diagonal was correct...he readily agreed.
The good thing was, I scored about 50lbs of screws in my tool pouches...for my stash. I did the addition part vertically...not the best, but better than diagonal, using the old siding.
I agree, tear it off..and re-do.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
Thanks for the replies so far. Looks like I've some work to do regardless of which remedy I choose.
Mike Smith discovered that the photo I'd attached wasn't of my diagonal siding. Whoops! This attached file is the photo I'd intended to show. As suggested by Ed Hilton, I've reduced the file size to be less than 100kb.
However, the quality is not great. I'll post again with the original file, which although better quality is about 500kb large.
John
John, except that you're standing kinda far back, the smaller picture looks good. Interesting siding pattern. I would have expected a chevron design or something. Looks like somebody's idea of a practical joke.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
This is the photo I'd intended to show. (File's about 500kb.)