Top 7 Mistakes While Constructing Accessory dwelling Units (ADUs)

ADU construction is just like playing a puzzle in which every block matters a lot. Similarly, every dollar counts while building ADU.

ADUs are a big investment, so we know that you want to save money in every way possible. Unluckily, we have watched many homeowners who got badly affected by the ADU mistakes that cost them thousands of dollars.
As the best ADU instructor, we have supervised and helped hundreds of homeowners through their ADU building projects. We ensure to take them away from the options that could blow their budget, either throughout the construction process or in the future.

While designing or constructing your ADU, avoid the following 7 mistakes. Let’s get into them.

1. Alterations while ADU construction

Change orders are the death of acquiring a cost-effective ADU. If you make a change in ADU construction then it will affect elsewhere in ADU, that’s why we have put such an emphasis on seeing the design in 3D, virtual reality and augmented reality before one nail has been hammered.

ADUs are small units, so even something as small as increasing one foot in a closet can lead to moving electrical, plumbing, drywall, framing, and then painting. Your general contractor has to call all the workers back to demolish and then reconstruct that. Extra working hours for workers can be pricey and you will also have to spend money on extra materials.

Changes also lead to delays in the remaining construction process and many contractors demand payment for that.
The appropriate solution for this is to study your ADU plans carefully with your designer so you don’t feel like you don’t have sufficient storage area or don’t really know the bathroom size.
Never make changes in the construction phase; do all these changes in the designing phase before submitting permits.

2. Hiring an inexperienced designer for your ADU

Do you know an architect that is experienced and constructed some lovely homes? Well! That’s perfect, but you really require an architect that has experience in designing ADUs. The requirements and laws for building ADUs are quite different from a single-family home.

ADU designing is a very difficult task. Give it a thought: your ADU designer has to gather all the essential components of a normal-sized house, like bathroom, kitchen, and bedroom, in a limited space.

Not only that, designing ADU is like playing Tetris; they have to fit ADU in a space that has a house already. They have to take care of keeping the privacy of both the ADU and the main house; getting sufficient sunlight in the ADU while keeping that privacy; designing ADU in such a way that it can have access to the road; and if possible, making a little outdoor area for the ADU.

And the main thing is that they have completed all these tasks while sticking to local, neighborhood, and state regulations.

A new designer will cost your money and your precious time.  A designer who has no experience in ADUs will have to explore all the local and state regulations and will not be prepared to deal with city planners who don’t know what you’re legally allowed to construct.  It means that you are not getting the desired ADU or paying for services or items you don’t want.  Experienced designers make every decision while considering budget, space, regulations, and long-term return on investment.

Let’s have a look at an example: San Jose, a city in California, needs all ADUs to be electric.  It will have an impact on the design of ADU, right down to the water heater.  Electric tankless heaters are small in size but are pricey, and homeowners get frustrated at their price. Standard-sized electric water heaters are inexpensive, but in San Jose, building regulations need them to have an enclosed space of 12 square feet inside the ADU.  In an ADU, 12 square feet is plenty of space. It can be a large kitchen, an office nook, a large bathroom, or a big closet. More functional space implies that it’s a more desirable rental unit. An experienced ADU designer is well aware of all this. He will make decisions that will not only save your money but also benefit you in the coming future.
We have assisted hundreds of homeowners in finding the best experienced ADU designers.

3. Expanding garage conversion in a false direction

Garage conversion ADU can be stretched economically, i.e., in direction of the pitched roof using a non-load-bearing wall.   The most affordable method for a garage conversion is to construct within the current footprint, but if you are searching for a little more space, there is a secret that a lot of people don’t know. You can extend a garage more cheaply and expensively; it all depends on you!

Cheaper method: extend it towards the garage door. Two non-load-bearing walls and two load-bearing walls are used to build most of the structures. A load-bearing wall is exactly as its name shows, i.e., it sustains the majority weight of the building.

The wall next to the garage door will be non-load bearing in most of the garages. Expanding garages from that is the cheapest solution as there is no need to do structural reinforcement or demo. It’s also relatively cheap to go through the wall in front of the garage door since it’s probably not even load-bearing, although you’ll have to spend some money for demos.
You want to prevent extending from any other side, especially if you just trying to get some extra square feet. Those walls are load-bearing and will need additional reinforcement. It will be more expensive to extend the roof in that direction.

4.  Not separating the utility meters

Homeowners get shocked when they came to know the price of installing separate meters for their ADUs. The price can be $2000 or even more than $5000 for one electric meter.
But it appears reasonable to invest money now so that the residents can pay their bills in the future. Here are a few reasons :

  • First, rates of electricity are tiered. homeowners who don’t install separate utility meters have two houses using electricity on one bill. That leads to an expensive tier because of high electricity usage.
  • Secondly, homeowners who add bills to the rent are at a loss because it is difficult to interpret how much utilities of your tenants will cost and ask for rent that will cover it.

People understand this during the difficult times of pandemics. Everyone was doing their job from home so the electricity bills went up, and homeowners whose ADU rents involved bills had to bear those prices. There are chances that Remote working will stay for long, so your ADU tenants will be using utilities day and night. It would be perfect if they pay their utility bills.

It’s right that many homeowners put solar panels on ADUs which can lower their electricity bills. But nobody knows about the future of utilities including electricity, water, and gas.
ADUs are the best and long-term investment units. If you wish to rent your ADU then install a separate utility meter as it will save thousands of dollars in the future.

5. Not optimizing wet walls

ADU design professionals are aware that the most cost-effective way to design plumbing in an ADU is to install a bathroom, kitchen, and washer on the same wall. Of course, they lie on different sides of the wall. It is the only wall that has all the pipes.

Sewer and fresh water pipelines rise through the foundation under the wet wall. Having only one wall saves on channeling and also the special waterproofing materials needed for plumbing walls. If it is all along a single wall, it will be easy and affordable to access the plumbing for repairs later.

6. Complex roof lines

If the roof lines of your ADU are unique, it leads to expensive ADU. Roofs are kept up by a wooden support system known as trusses or rafters. Prefabricated trusses are used to build standard roofs, such as gable, hip, or shed roofs. These trusses are cheaper than site-built rafters. Most prefabricated trusses are stronger.

Rafters are customized and used to build unusual roof lines, which tends to increase the labor salary. Experts say that the cost of using prefab trusses is 30%-50% lower than building traditional rafters on site. Roofing with many angles is also more pricy than installing a simple roof.

7. Hiring a general contractor who has no experience

We know that hiring a general contractor that offers lower rates is tempting, but think that are you really saving your money? Be careful of appointing the one who gives you an extremely low price compared to what you received. It can indicate that they are unlicensed or have no experience in their field.

Remember! It is not only renewing your kitchen model. It is a complete home where someone will live, so why do you compromise their comfort and safety just for saving just a few dollars? It can also cost you more in the long run.
If you hire an unlicensed contractor, it can result in shoddy workmanship, long build times, or in the worse case, hiring someone to escape with all your money while you are sitting in a dirty building site in your backyard. This has happened many times and we have seen it!

When it comes to releasing contractor licenses, many states do not mess around. Most states demand contractors to have experience of a few years, complete the process of submitting an application and obtain liability insurance. If you hire a fully licensed person, you don’t have to worry knowing they are appropriate for this job and you are safe.

Final thoughts:
This is why hiring suitable people to design and construct your ADU is so important.

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