Types of housing for mother in law unit
May 15, 2017 12:59 PM   Subscribe

We are seriously considering putting a mother in law unit in the backyard. Of course permits and zoning laws need to be confirmed with the city first before anything can start. We're in the meantime getting ahead of ourselves and exploring the pros and cons for different types of house buildings.

1. On-site building. I assume this will be the priciest though perhaps the most customizable.
2. Modular homes. We like some of them and my understanding is they follow the same local building codes. One question I have is "Is it possible to get modular homes for $50k or so?" Looking for about 500 sq ft. I'm in the Seattle area and so far that is an impossibility. I've looked at greenpods, methods and others. Seems they're geared for luxury housing with price range nearing or even exceeding $100k even for the smallest models. I just need a simple though good quality building. If so - do you have recommendations? I did find modular homes for that price range in Texas.
3. Park Models - Seems to be the cheapest option. My understanding is they're classified as RV and follows different building codes. What are the downsides of park models as mother in law unit (permits permitting of course)?
4. Tiny homes on trailer. Not favorite choice - too small and from my understanding the legality of it is still in limbo.

I am so far leaning towards #2. Maybe even order one from Texas and eat the travel cost. Though I would like to stay as local as possible assuming I can find a local builder that meets my needs. If you've dealt with something similar, I would very much appreciate into any insights you can offer me.
posted by 7life to Home & Garden (14 answers total) 2 users marked this as a favorite
Are you hooked up with the DADU and/or tiny house community in Seattle. This kind of info is hard to come by (especially with how the regulations were expected to change but that died on the vine) and what I've learned is mostly word-of-mouth. I've been out of the loop the last year or so, but talk to Peter Wolf at Coho Realty and he can let you know if there are any workshops coming up.
posted by matildaben at 1:52 PM on May 15, 2017

FYI, friends of mine looked into Green Pods here in Bremerton, and they were told that these units do NOT meet code. Surprised me, but thought you should know.
posted by dbmcd at 2:02 PM on May 15, 2017

Many tiny houses use a ladder or steep staircase to a sleeping loft. That may not be the best choice for a retiree living alone. They are more in the 150 sq. ft. range, and are often on trailers, so probably not something you want for her, but it seems worth mentioning.
posted by Cranialtorque at 2:37 PM on May 15, 2017

This park model RV that looks like a cottage might be worth checking out: http://www.escapetraveler.net/classic. (They have some models cheaper than that one, and financing).
posted by pinochiette at 2:42 PM on May 15, 2017

If this is actually for a MIL, maybe consider a 'granny pod'? Med Cottage seems to be the top hit on the webs.
posted by PorcineWithMe at 2:45 PM on May 15, 2017

We looked into doing this. Our take away was that anything external that we added would not add value to our property. An RV type unit probably would have ideal in terms of ease of installation and cost plus retained resale value, but ultimately it was not an option for us due to mobility issues. In the end we chose to remodel the house and add a small bed/bath suite.
posted by vignettist at 3:04 PM on May 15, 2017 [1 favorite]

So, this is entirely dependent on your specific jurisdiction (Seattle area won't cut it to answer these two, you need your city or other governing body ID'd), but most metro areas have ordinances against #3 and #4. They're just not legit for most places.

Here in Portland for example, you're not allowed to inhabit an RV parked on private property. You can store it there, but living in it is a big nope. This goes for sketchy meth winnebagos, as well as fancypants tinyhomes on wheels. Basically, you need different zoning and infrastructure to make this happen in most places.

Hiring a contractor to even evaluate what might be a good option for you is worth the cost and should be chocked up to preventative planning cash; they're the expert and they know the codes for your area.

Based on my research (down here in Portland, so YMMV slightly), your price point probably won't be realistic for a 'full' cottage/ADU (kitchen, sewer hookup, water, electricity, etc). I mean, I think up in Seattle proper, just the permits alone will run you almost a 5th of that budget, and the actual hookups themselves need to be budgeted into that as well. ADU's are cheaper than a whole house, but they're not cheap. Cost/sqft is oftentimes much higher than building a larger house.
posted by furnace.heart at 3:07 PM on May 15, 2017

You might want to look into just having an addition built onto your house which would likely make hooking up water, sewage, and utilities a lot easier.
posted by mareli at 4:30 PM on May 15, 2017

Yeah, we're in Seattle city limits and after much research we decided to do an addition and convert the basement to an ADU because the permitting and financing for DADUs are just too difficult and costly right now. That's why there are so few DADUs here right now.
posted by matildaben at 5:42 PM on May 15, 2017

in my very rural area if you don't install an oven it is not considered a "home" and therefore does not need a permit. can you put a "bed/bath" in your backyard easier than a tiny home with kitchen? or is no kitchen a deal breaker for you?
posted by cda at 5:43 PM on May 15, 2017

Have you seen this: Establishing a Backyard Cottage, published by the Seattle Dept of Construction and Inspections?
posted by she's not there at 9:21 PM on May 15, 2017

There's a bunch of these IdeaBox homes in Port Townsend. My friends have one and they're really great.

I also quite like Modern Shed.
posted by humboldt32 at 12:44 AM on May 16, 2017

>>"Is it possible to get modular homes for $50k or so?"

Not that I've been able to find.

I have some issues with mobility, so I wouldn't consider a tiny house for myself. Also, legality, etc. But I've certainly considered the modular & conventional construction.

I wonder how Park Models age? They seem a little too RV-y.

A few tips on getting money back out of an ADU.

While you're getting ahead of yourself... I love looking at Accessory Dwellings - less shiny, more crunchy.

According to a 2014 blog post by Eli Spevak (who's kind of a big deal here around ADUs/granny flats):
  • Detached ADUs cost $13 – $438 per square foot (mean is $151/sf)
  • Attached ADUs cost $6 – $308/sf (mean is $82)
Part of the reason that they cost so much is kitchens and bathrooms which are crazy expensive whether or not the rest of the house is small. More on cost.

Detached bedrooms are also an option. And cheaper.
posted by vjpdx at 11:27 AM on May 16, 2017

Went down to the permit office and it's moot point since they allow DADU where I am if lot size is 3.75 acres! I'm in zone RA-5.
Option now would be ADU or ALQ (oven-less detached unit per someone's suggestion up there).
Original idea was to move into the unit and rent out the main house (either to in-laws or actual renters). Oh well :)

Thank you for all the replies though. Appreciate them.
posted by 7life at 3:54 PM on May 16, 2017

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