Do you want a smooth transition, or do they? i've worked with casing and baseboard that are the same thickness lots of times. we just butt it up to the casing, even if it's all flat profile.

But if you really want them to tie in together, i would just glue where they meet, then fill and do lots of sanding until there's no noticeable transition

 

Thanks! They want the smooth transition. The carpenter I used to work for all ways told me to make sure the base is a little thinner the casing so the casing has a little lip and that was the right way of doing it.

This is the first square trim that I have ever done, so I'm thinking of butting it against the casting, fill the little crack with clay, sand it and paint it.

 

Do they want the joint to be invisible? in paint grade material?

 

Not visible, they want it to be like a smooth transition that looks like one piece.

We are using paintable (primed) MDF for casing and base

 

that's about all you can do. I have done it where I sanded a slight roundover profile on the end of the baseboard, but then there is a visible crack where the two meet which is obviously not what you want.

 

The casing will already have a round over. you need to at least put a round over at the end of the base.
You will struggle and fail, and it won't be your fault. it just is. Flush is impossible 100% of the time.
There is a 1/2 x4 base just for that.
Best bet is to show the clients how it will look

 

Seen it, done it. It looks a little weird but it's their house and if that's what they want fine. They're cutting the check and I don't have to live with it.

To get a smooth finish I like to use Evercoat automotive Spot-Lite spot putty. Like bondo but smoother and easy to sand.

 

Little caulking, a little paint...:laughing:

 

I just did some pre finished clear maple trim in a home where we used 1x4 for base and case. It's not rocket science to flush out the joint, it just takes some fiddling.

 

I don't like the flush look either, but if they want it, I would probably throw some biscuits in too.

Brew

 

I've run into that...... and to keep the base trim/ casing exactly flush, I drop a formica sample shim behind the butt joint. For invisable though, you still have to fill/sand.

 

In most cases it is nice to put a base block, it will make a nice transition and you don't have to worry about being to deep or not being flush. It will eliminate extra labor like you said, caulking and filling, sanding,etc if they don't match up perfectly, not to mention it will look like s^*t if they don't, even with sanding and filling.
Try explain this to the HO and make a sense out of it, they might change theirs mind, was in a few similar situations and they were happy with the outcome.

 

1 by 2 casing?

Filling joints with clay?

Is it just me???
LOL

 

Exactly. Even if the doors/jams are perfectly centered in the opening, 2" (really just 1-1/2" wide) casing probably won't span the gap. The joint between the casing and the base is probably going to be the least of your problems.

 

99.99% of the trim I install is the same thickness as the casings. Usually 1x6 base and 1x4 casings. Is that not common in the rest of the country?

 

Plinth blocks, or defined joints,
Flush is a huge pain.

 

99.99% of the trim I install is the same thickness as the casings. Usually 1x6 base and 1x4 casings. Is that not common in the rest of the country?

It's not that common around here (Boston)
Where are you?

I'd say 90 percent here is moulded casing.

Yes it can be done right. Yours looks good.

 

Maybe some of the R.O.s for the doors you set are large, but mine are typically only 2" larger. 2'8" for a 2'6" door. It leave around a 1/4" shim space. 1 1/2" casing would cover just fine.

Here is the job I was referring to...

http://s1324.photobucket.com/user/Punchlist_Carpentry/media/1913/12101212303_zpsea02884a.jpg.html

We came back about a year later to replace those corner guards, replace all the painted door in the hall with clear finish maple as well as new base/shoe/casing down the hall.

That picture is not 1" by 2" casing.

Show me a picture of your 1" by 2" casing.

1" by 2" would never work for me. My jambs are almost 1-1/2" thick plus I'd have to take a sick day just looking at it.

 

That picture is not 1" by 2" casing.

Show me a picture of your 1" by 2" casing.

1" by 2" would never work for me. My jambs are almost 1-1/2" thick plus I'd have to take a sick day just looking at it.

That is the 1x4 from I talked about before and those are some mighty heavy jambs you got. I use 3/4 stock, 1/4 shim space. Leaves 5/8 covering the rock when you use a 1/8 reveal. I could see one by two looking fine in a very minimal house.

 

cut door cassing tack in place cut base biscut cassing to base pocket screw base to cassing bon do the joint.. a lot of work.
you can use veneer tap over the joint and sand flush