Why the covered porch and bay? Do one or the other. There's no benefit to either the way it's drawn.

Yes, it's expensive.

I don't understand your reasoning "Do one or the other". I want the covered porch, and the bay is to add space to make that room larger. There is benefit for both.

But what will the porch be like, with that bite taken out of it?

If the porch is 29'3" x 11'10", I assume it's 11'10" deep. Subtract 4' (more?) for the bay window, and you have a sizeable chunk of porch which is less than 8' deep. Will that affect how the porch functions?

Whether or not it is expensive depends to some extent which way the joists run. If they run the long way of your dining table, then it can be cantilevered over your basement (no need for basement foundation to follow the same)...

I think, if it were me though, I'd simplify it and just do a rectangular shape instead of the angled corners (and I have an angled area for my dining table). It will make more sense for your covered porch, imo.

The bay renders the porch an unusable space by occupying the majority of the space. The porch blocks the light to the bay, which is a primary reason for doing a bay instead of a plain rectangular shape. They're mutually exclusive constructs.

GreenD, the bump out doesn't take up too much of the covered porch. The windows will still bring in light. If there were no "bay", would you not expect for windows to be added to that wall (which technically would get less light because they are further recessed under the covered porch). They are not exclusive designs in my opinion.

MissingTheObvious, yes I'm quite aware of how much it affects the covered porch and I am fine with it.

Kirk, thanks that makes sense.

I'm ok with the design, I'm not asking for a critique on it. I appreciate all the answers to my actual questions regarding the need for a full basement under the area, and the cost on such a space.

But what will the porch be like, with that bite taken out of it?

If the porch is 29'3" x 11'10", I assume it's 11'10" deep. Subtract 4' (more?) for the bay window, and you have a sizeable chunk of porch which is less than 8' deep. Will that affect how the porch functions?

Well, if you want to spend a bunch of money making your home less valuable for resale, we sure can't stop you. :-D We can only tell what the next potential buyer of that home is likely to think.

Here is a link that might be useful: Cost vs Value 2015

Look GreenDesign, I never asked anyone's opinion on design. I only asked about structure and cost. Please feel free to ignore this thread from here on out.

If you really want to give your valued an professional opinion to someone, please seek out the original designer. Here is the link to the original plan. Have fun.

Here is a link that might be useful: Original Plan

You seem a little stressed, Sean_S. Perhaps you are in Boston and getting even MORE snow right now . . . . . .

i agree with kirkhall, i'd change it to a rectangle
i'm thinking your porch will still be a very nice size
don't have a clue about the basement question

at times i find people on gw to be a bit opinionated
but i still value the website....

Thank you okokok. I agree with your last statement as well.

OK, I was going to give my opinion because we are building a house with a rectangular bump out, but I won't cause I don't want to get yelled at.

If your original floor plan is the one you linked to, also consider that the kitchen will be dark (being interior as it is) and also that with the table turned in the direction you have it, it will extend even more into the walk-way that is already quite narrow/non-existent between the laundry/backdoor.

You might instead consider a wider bump out and/or a buffet/booth type setup for your table, so it can be pushed as far toward the windows/bump out as possible.

I don't think I've ever seen a bump out bay window under a porch roof. I looked around for examples and couldn't find any. I think it will look quite odd.

I would definitely look at plan elevations with the bump out added before committing to it, especially because it probably will be quite expensive. You may just want to end the porch before the bump out.

To answer your questions maybe and yes. You can minimize the risk of drywall cracking from the cantilever if it is stiff enough and properly installed. But the rub is, I would think that the bumpout as a slab on grade or basement would be cheaper than a properly installed cantilever, and it would look better. Dumping a bit of concrete into a bumpout is almost nothing, and building the forms is not going to cost you that much. The additional costs of the pour are going to pale in comparison to the other costs of that bumpout.

I looked at the architect's plan and I wonder if he ever built this house. I think many people here are concerned about price vs benefit of that particular element of the design. I mean you may love the bumpout, and you may love the porch, and you may love them indivdually enough to overlook the obvious problems and be happy with them, but when you are living in this house I promise you that you will notice it. The plan the architect drew has a bay bumpout onto a covered porch with doors to either side. That is a huge hunk of space that you can't really put furniture in because of limited space, huge windows into the house and walkways. You are basically just paying a big chunk of change to put a roof over sidewalk.

If I was married to that plan, and needed the space in the eating area, I would shrink the covered porch to the door out of the great room and use the money you just saved to add two feet to the entire back of the house. After killing that much roof and that bump out you should be just about even.

This post was edited by Bry911 on Sun, Feb 1, 15 at 2:25

In our area, cantilevered bumpouts are usually used simply to meet setback requirements on narrow lots (for fire protection), as the setbacks are measured from the basement foundation, not the bumpout. (Though the bumped out area is limited by code to a certain maximum).

It should be considerably cheaper to pour that bump out into your basement foundation. Are you doing a finished basement? Maybe it would be a nice nook area in a room.

We had a bow/bump out area in a home in Oklahoma that we owned and there was a nice front porch roof over the top of that area and it looked just fine and was never mentioned as a deterrent when we sold it. Many visitors actually commented that they liked it.
The above home was a slab home but if I was building on a basement or crawl space I would make the bump out part of the foundation....I've saw too many bump outs settle and pull away and this was probably from improper compaction.