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Exterior trim size?

JohnWalker's picture


I am about to have my exterior window trim installed on our "craftsman" style home. Its a new build with 32w x 44h windows either singularly or in groups of 2 or 3.

My question is how do you go about choosing the width of the exterior window trim? The vinyl windows have almost a 3" wide frame. I will be adding either 5/4 x 4, or 5/4 x 6 trim.

Does anyone have any tips or guides for sizing trim?



john (post #206951, reply #1 of 4)

The trim is not just a single element but must be taken as a whole with the rest of the design.

You say the windows have an almost 3" wide frame-do you mean the sash of jamb?

Can you post a photo of the house so someone can suggest a trim that complements the style?  To me, craftsman style suggests the wider.

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Proportions (post #206951, reply #4 of 4)

I appreciate all the comments and agree its about proportions, on many levels.

From the high level down to the detail level:

1) Proportion of window area to wall or siding area on any given elevation. In our case the two main exposures, Front and South Side are not an "ocean of siding" but rather broken up nicely and with attention to symmetry & placement relative to other architectural details. The front dormer is about 6% window.

2) Proportion of window trim area to window glazing area. In our case the windows are not huge so very wide trim would look over powering. (In the extreme I've seen 24" square windows with 8" wide trim applied and it really looks weird, like you replaced the windows with undersized off the shelf units because you were in a hurry).

3) Proportion of clapboard siding exposure to window trim width. I can see this might be an issue but we are not getting that fussy about 6" vs. 7" hardi plank exposure.

4) Trim, sash, siding colour combination, although not really a proportion issue the use of 2 vs. 3 colour combinations creates its own proportion. We are going with cream trim and sage green siding. So 3" white vinyl sash with 5-1/2" cream trim looks like 9" of light coloured trim. The effect would be quite different if we went with sash contrasting trim even skinny metal windows. 

With that said and the benefit of the attached photos i would really appreciate further specific comments.

(I may end up mocking up one 1x4 and one 1x6 frame on the front just to see.....)

Thanks in advance for any insights.


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John +1 Totally agree; the (post #206951, reply #2 of 4)

John +1

Totally agree; the width of the trim--like the width of siding--is mostly an aesthetic decision based on things like the area of siding on any given wall versus the area of windows, as well as design canons like those characterizing A&C (Craftsman). In general, A&C opted for wider window/door trim to add to the "massive" and "medieval" appearance (totally opposite, I believe, from the Asian style elements which also formed part of the A&C lexicon). When I recently resided my house, I went from 6" wide siding (barely 5" exposure) to 7-1/4" (6" exposure), and wherever possible I went with 2x6 WRC for trim in place of the Japanese nominal 2/4 cryptomeria that was originally installed. I think the wider trim has the effect of drawing eyes to the windows rather than the ocean of siding on certain sides. IMHO I think it makes the house look more solid. (The US nominal 2x6 also was thicker than the original cryptomeria, giving me a bit more coverage of the siding edges, important since I was also installing a rain-screen that pushed the siding outwards a bit.)

  This photo comparison is really unfair, since the old photo is when the house siding/trim was rotting at 16 years old, while the new photo was taken shortly after I had finished resided the house, but I think the windows do show better with the wider trim (I couldn't use 2x6 trim on all windows, mostly due to proximity to other elements).





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Not sure where you are, John. (post #206951, reply #3 of 4)

Not sure where you are, John. In the US, lumber comes in standard sizes. 5/4" x 6" actually measures about 5 1/2" in width. To get 5" you would have to rip 6" down, to get 6" you have to rip 8", which is 7 1/4".  You didn't say what type of siding you were using. Although it isn't always possible,  with horizontal sidings like clapboards, it's often desired to have the butts of each row come even with the tops and bottoms of the window trim.  Instead of all the rows being 4", for example, you may run several at 3 7/8"  so the siding comes even. It's not unusual for there to be a window or two that are a different height  and  adjusting rows of siding doesn't make sense for those. Some types of siding can't be altered and, today, many installers don't bother trying to make the rows come even.

Wood moves across the width, the wider the board, the greater chance it will shrink or cup. Other details, such as corner boards and proximity to adjacent windows, doors and corners should be looked at. You may not want the siding to only be 1/2" wide in between two windows. Size of the house can be another factor. 6" wide trim may not look very large on a 3 story with large walls but it could look huge on a small ranch. That may be the look you want or not. A lot of these details depends on your taste as well as the particulars of your situation, you have to think ahead with some of the circumstances.

This house isn't Craftsman style and it's pretty large. I used 1x4" side trim on Anderson windows which only have a thin perimeter. The bottom trim may be slightly less wide, I forget, to come even with siding rows as well as the top headcasing, which is around 6". I planned it so rows of shingles didn't have to be "cheated".

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