House Design Suggestions
House Design Suggestions
My family member is building a house in northern IL. She is building it through a program with the local high school where the students do most of the work with the teacher acting as the contractor. They’ll subcontract out some of the MEP, masonry, and earthwork but the majority of the other work will be done by students.
I’m trying to help her plan out the design to be sure she ends up with what she wants. She has purchased the property and the construction will begin next semester.
She would like a house that promotes healthy living with lots of fresh air, sunlight, and as many low VOC and nontoxic building materials as is possible. She is also working with a limited budget, hence the student labor and likely 2yr build schedule. I am also trying to incorporate as many energy efficient options into the design as I can.
Can you provide any suggestions or comments regarding the design we’ve put together so far? Anything that will increase the functionality, efficiency, buildability, health, or decrease the cost would be appreciated.
Some topics we’ve been batting around: Gas or heat pump? If they go gas, should the go gas for everything? Where to put the ductwork and keep it in the conditioned space? Best insulation setup for the roof and the walls? If we do the plenum trusses will the throw from the diffusers be enough to keep the spaces comfortable?
Thanks for any comments or suggestions.
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If you tried to attach a design, it didn't stick. I'll immodestly suggest the book I co-wrote as a resource, because we wrote it specifically for people like your family member. It's called Pretty Good House and was based largely on discussions on the topic held here at GBA over 10+ years. (I am not pitching it to make money; a very modest royalty split four ways does not go far.)
A shop teacher in Taylorville, near Springfield, Il, uses the book as part of his program, and they also build houses.
More Pretty Good House resources here: https://www.greenbuildingadvisor.com/?s=pretty+good+house and here: https://www.prettygoodhouse.org/
Yeah, I'm trying to load the plans but I just get the spinning wheel for hours. Thank you.
Beat me to it. I also recommend Michael's book as the starting point and ending point.
Site
1. Start with the site. Organize the house to maximize the site's benefits and minimize its flaws. I generally try to place bedrooms to get east light, and shared space to get south light. Place utilities/storage/mudroom at the north.
Space Planning
2. Plan your spaces from the get-go with a thought as to furniture placement. Draw furniture on your plans from the start. This will guarantee you've got good traffic flow, adequate space, and no more space than necessary. Also itemize storage needs and include that as well. Well designed storage can help minimize floor area.
3. Try to minimize exterior corners. Keep to a rectangular plan. Place the primary bedroom in a corner where it can get light from 2 directions, with one being east.
Building Shell
4. You are in climate zone 5a, cool-humid. Your most economical R-30 wall would probably be 2x8 studs at 24" on center, with 2 layers of R-15 fiberglass batts. Your wall assembly from inside to out would be: 1/2" gypsum board, variable perm membrane, 2x8 studs with batt insulation, 15/32" OSB sheathing, taped sheathing joints for additional air barrier, unperforated building wrap such as tyvek, 1x4 strapping for rain screen, horizontal lap siding. The 2x8 stud work is a fairly new thing. There are other ways to get the required r30 insulation. But this is probably the most direct, requiring least special skills, and using readily available, relatively low cost materials. Exterior insulation systems typically make door and window installation much more complicated and requiring more special skills. Interior insulation systems (Mooney wall, double wall ...) require additional lumber and labor.
5. If prefabricated roof trusses is an option go with those. Get raised heels. Blown cellulose in the attic is the cheapest way to get plenty of insulation. Ventilated attic. don't put any equipment or ducts up there. Go for r60 even though code is probably R49. It's almost no additional labor and the materials are cheap. So, you get good value.
Mechanical
6. Don't put mechanicals or ductwork in the attic. Put mechanicals in a utility room and plan key spaces such as the mechanical room, corridor to bedrooms, bathroom ... to have dropped ceilings, allowing ductwork to reach spaces that way.
7. Build the tightest envelop you can, paying special attention to air infiltration. That is even more important than insulation levels. So, get a blower door test and take advantage of it to identify leaks. Doors, windows, exterior wall penetrations for things like outdoor faucets and plugs, and recessed ceiling lights are the biggest culprits.
8. Having designed a compact and tight house, you've minimized your heating/cooling requirements. Don't get oversized mechanical equipment. It should be sized based on your actual needs. Your AC needs should be minimal. Heating is more the issue. With a compact floor plan you may be able to get away with the simplest air-to-air heat pump system, which is probably the most economical to operate.
Random thoughts
9. Have a mudroom! It can do double duty as a side door, utility room, laundry room, storage. Have enough space to hang a wet overcoat and to take off muddy boots. Have space for a chair. With a good mudroom you can probably get away with just a carport rather than enclosed garage.
10. If it were my house I'd skip AC entirely, relying on cross ventilation in the summer. Then I would build the house on a slab on grade, incorporating hydronic floor heat throughout. This wouldn't be the cheapest up front option, but in my book it would be the most comfortable. Your water heater could do double duty as both your potable water supply and your floor heat source. This is advice that others on GBA would disagree with. So I'm putting it at the end here.
11. Read up on "aging in place" design and do what you can to incorporate the principles.
Best of luck on your project! I hope to see updates posted here.
Antonio, Thank you for the detailed response.
1. We actually did this although I don't know if was by accident or my sister planned it.
2,3. Looks like we got this covered. The kitchen might be a little tight but I think we can make it work.
4. Interesting. I believe we were planning to go the 2x6 route with exterior CI. I haven't checked the local code but I assume it is a few years behind the current IECC requirement of r30. This needs to be hashed out.
5. The route you describe is how I am trying to steer my sister but she may overrule me on this one. I think she wanted to go mineral wool.
6. This is one area where we're struggling. I was suggesting plenum trusses, which are just storage trusses with a sealed off area for a plenum. The builder is suggesting doing 10' ceilings with drop ceilings below at 8'. This has been one of the more difficult decisions since we're trying to keep things cost effective but keep the ductwork within the conditioned envelope. The section M301 in the post below shows what I'm suggesting but I'm open to other ideas for sure.
7. This is a good point. I will add the blower door requirements to the mechanical sheets. This is one thing I've always struggled with, how do I ensure this is accomplished though? Is this on the mechanical contractor or the GC?
8. I performed an energy model and came up with a 36mbh heat pump for the house which is about 1200sf. That is what I am suggesting. My sister is saying that most people in the area have gas heat and I think their inclination is to do what most do in the area but a heat pump would be less expensive for sure since a new gas line won't be needed if they go that route.
9. Check.
10. This is funny that you comment this. That is what my brother in law wanted to do but I suggesting they avoid the in-slab heating, lol. The plan is to have window and/or doors across from each other so that the whole house can be ventilated by using windows and doors. This was actually a requirement from my sister. She is kinda new to the whole home design but she must have read up on it a bit. Maybe we can revisit the in-slab heating. There will be a backup wood stove. I think I forgot to add that to the plans.
11. 10-4.
Thank you for the suggestions.
Well, I finally got one sheet to load. I guess I won't be able to share most of the others but if there's anything in particular you'd like to see it looks like I can at least load individual sheets.
There is a small floor plan on the first sheet; could you share a larger version? It looks pretty well thought-through to me. You'll want more space between the island and southwest bank of kitchen cabinets.
Michael, there is a full plan in the main post. I edited it in order to add it. Unfortunately it seems I can only load one or two drawings at a time and have 16 so far.
Yeah, that was one of my fears as well. In order to have enough room in the utility room we squeezed the kitchen and bedroom #2.
I'm all ears for suggestions on a better layout. We've batted several around and finally landed on this one. I was going to specify that the island not be permanently fastened so that it would be a "floating island" if there is such a thing that way it could be moved or adjusted if need be.
A couple of ideas
1) you could remove the hallway window to get more closet space.
2) as others have said I don’t think you have enough space for the island and dining table. You could get rid of the island and have a larger eat in kitchen or try and do a built in style banquette dining area.
3) Do you need 3 exterior doors? I would not install a sliding door, they leak too much air and can be uncomfortable to sit by
I would make the utility room smaller and the kitchen larger.
Since are already doing an area within the conditioned envelope for the attic ductwork, consider a ducted mini split. They are very small, so you could put it in the same area in which you are installing the ducts. Then the only things in the utility room are a water heater, the utility sink and the W/D, and it can be smaller. Move whatever is on the other side of the closet closer to the door and make the closet larger. Consider turning the full bath 90 degrees to also make the closet wider, and it can be the primary bedroom. You would have similar wall space in the utility room.
Consider future options as well. I'd install a floor drain in the utility room so in the future you can expand the half bath to a full bath with shower, with stacked W/D.
If you are considering aging in place, make sure there are no step entrances, place the switches lower and the outlets at 24" aff. Also use filter grills for return and place them where you don't need to get on a ladder to change the filter. Also place the ERV where you don't need to get on a ladder to change the filter.