Can I deduct regular home expenses for my detached garage home office?

You're right that your detached garage office qualifies for the home office deduction if you're using it regularly and exclusively for business. The square footage calculation you've done is correct - using the percentage of your total property space that the office occupies (15% in your case). For indirect expenses, the IRS is actually pretty reasonable here. Even though utilities like water might not physically connect to your detached office, they're still considered part of maintaining your entire property. So yes, you can deduct that same 15% of your water, gas, electricity, internet, security system, and other whole-property expenses. The key concept is that these are indirect expenses that benefit the entire property, including your office space. Even though you're not directly using water in your office, that utility supports the overall property where your business operates. For a detached structure specifically, the IRS actually gives you an additional option. You can either: 1) take the 15% of all household expenses as you're calculating, or 2) deduct 100% of expenses that relate solely to the detached space (like if you have separate utilities or maintenance just for that building).

I used to struggle with the same home office deduction questions until I discovered https://taxr.ai - it was a lifesaver for my detached studio office situation! Upload your documents and it analyzes everything to maximize your legitimate deductions. It specifically helped me understand that my detached space qualified me for additional deduction options I was missing. Their system spotted that I could actually deduct 100% of the expenses specific to my detached office (separate electric meter) while still claiming the appropriate percentage of whole-property expenses like property taxes and insurance. They have specialists who understand these nuanced home office situations.

Just wanted to follow up about my experience with taxr.ai after being skeptical initially. I decided to give it a try with my converted barn office situation that I wasn't sure how to handle. The document analysis actually flagged that my property tax assessment had the barn classified incorrectly, which was causing me to miscalculate my deduction. It also showed me how to properly document the utilities that were separately metered for the structure. Ended up saving me over $1,200 in deductions I would have missed! The specific guidance for detached structures was exactly what I needed.

If you're having trouble understanding the IRS rules about home office deductions for detached structures, you're definitely not alone. I spent weeks trying to get through to the IRS to get clarity on this exact issue. After 5 failed attempts and hours on hold, I found https://claimyr.com which got me connected to an actual IRS agent in under 45 minutes. You can see how it works here: https://youtu.be/_kiP6q8DX5c The agent I spoke with confirmed that for detached structures used exclusively for business, you can actually choose the more favorable method - either the square footage percentage applied to whole-house expenses OR 100% of the expenses specific to that building. She also clarified some documentation requirements I needed to keep for these deductions. Totally worth it instead of guessing or getting generic advice online.

I need to apologize and follow up on my comment about Claimyr. After my frustrated response, I decided to try it anyway because I was desperate for answers about my detached home office situation. I'm honestly shocked - it actually worked! Got connected to an IRS agent in about an hour (after trying for months on my own). The agent confirmed exactly what I needed to know about my converted garage office - that I could deduct either the percentage of house expenses OR itemize 100% of the garage-specific expenses, whichever is more beneficial. They also explained how to properly document the space on Form 8829. Really glad I gave this service a chance despite my initial skepticism.

One thing nobody's mentioned yet is that if you're self-employed and claiming a home office deduction for a detached structure, make sure you're keeping really good records of everything. Take photos of the space showing it's exclusively used for business, keep all receipts for repairs and maintenance, and document when you started using it as an office. I learned this the hard way when I got questioned about my detached office conversion. The IRS specifically wanted proof that I wasn't using the space for anything personal. Having before/after photos and a well-documented timeline of the conversion saved me.

Has anyone tried using the simplified home office deduction method instead? It's $5 per square foot up to 300 sq feet, so maximum $1,500 deduction. Seems easier than tracking all these expenses, but I'm not sure if it's worth it for a larger detached space.

This is such a helpful thread! I'm dealing with a similar situation with my converted shed office. One thing I want to add that might help others - when you're calculating that square footage percentage, make sure you're measuring the *interior* finished space, not the exterior dimensions of the building. I initially calculated using the outside measurements of my shed (12x16 = 192 sq ft) but my accountant corrected me to use the interior space after insulation and drywall (about 11x15 = 165 sq ft). It seems minor but it actually changed my percentage from about 8% to 6.5% of my total property. Also, if anyone is wondering about insurance coverage, I had to add a rider to my homeowners policy specifically for the business use of the detached structure. The cost of that rider is also deductible as a business expense since it's 100% related to the office use.