I had Grennan Construction install a new roof approximately 4 years ago. It was the third time I have had the roof done, and Grennan was the ONLY company that did it RIGHT. Fred was very easy to work with and the crew he sent out was fabulous. I am VERY picky about the details and I think the lead installer was as picky as I was which is very rare. I would recommend Grennan for any task. I hate using contractors (I do most things myself) and these guys certainly surprised me and I am very happy with their workmanship. read more

Mr. Grennan, I read your response to my poor review of your company. I will set aside our back and forth disagreements regarding my many complaints. This response is simply to tell you that you should have checked your books before you replied to my post. you WERE paid. My check for $760 was sent on 12/13/25. Your company sent me an invoice showing a balance of $0 on 12/18/25 and your company cashed my check on 12/22/25. Once again, you respond without really checking on what has occurred. This seems to be a habit of yours in my opinion. read more

Originally, as you can see by our review below) we were very happy with the installation of our James Hardie board. Unfortunately we found out the hard way that Grennan Construction does not stand behind their work. During the installation they made a human error and did not caulk and apply flashing correctly which led to a leak to our dining and living room ceilings causing over $2,000 worth of damage. We have made close to 20 texts or phone calls to Fred, his employees or his office in an attempt to have them come out access, and effectively stop the leak. They told us it was fixed once, we had the inside of our home professionally repaired and painted only to have the leak return shortly afterwards. Go Elsewhere!! Was referred to Grennan Construction by a trusted source and they didn't disappoint. The crew was very polite and conscientious from beginning to end. The Hardie board installation looked good from day one and continues to look great. You should definitely use Grennan Construction if you the job well done at a fair price and on schedule. read more

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Great company, very professional. We contacted them to repair siding after wind damage. Repaired the damage & inspected the areas around the damage as well. Honest, quality work & fair pricing. read more

We hired Grennan construction in the summer of '24 to install James Hardi siding, new windows and new gutters on our home. The crew that did the work was excellent. While they were working, they informed us of some soft spots on our roof that we should keep an eye on. A few months later we were having insulation put in and they found a leak. I had been in contact with the owner Fred, so I emailed him to see if they could please come out and replace it as soon as possible. It was around the holidays and the weather wasn't cooperating at all, but they came out on a Saturday and finished up the job in one day. They gave us a great price too. It's refreshing to find an honest, hard-working company that is so dedicated to customer satisfaction. We definitely recommend them and plan to use them again for any other home renovations. read more

Grennan replaced our siding and trim with Hardie and windows with Pella on a large 2 story home. Once the materials came in, Grennan's crews were on site every day to get the job done. A couple of the windows were the wrong size (error by Pella) and there were a few other minor issues, but Grennan took care of them when notified. The work was done correctly and we are happy with the results. The cost was a bit higher than other companies, but it was worth it to get a job done correctly. I would recommend them for similar projects. read more

We had some siding repairs done and the work crew showed up on time and were very professional. The work was done in a timely manner and looks great! ItI ever need anything else done I will contact Grennan Construction. read more

Grennan put a new roof on my home: noticed that the sub-planking was totally rotted and installed new plywood everywhere. They offered great professionalism and a very competitive price. Highly recommended. read more

I needed some repair work on my James Hardie siding to be completed before closing the sale of my house. Fred Grennan, totally committed to customer service and satisfaction, help achieve the project completion in a compressed time frame despite rain and being short staffed. Exceptional customer focus, excellent communication throughout the project from estimating the scope of work until completion, quality workmanship. Don't look anywhere else. read more

I would not recommend this company to anyone. You deserve better. There are other companies that would appreciate hard working people and not treat them like crap. This company doesn't communicate about anything. Once they have your deposit, they don't answer calls. They don't respond to questions. The owner first claimed to be responsive. After the first conversation, he treated me like I was bothering him when I tried to find out when they would be starting my work. To this day, he has yet to call me back. After I complained to James Hardie, this company decided to have a worker call me to tell me he was coming the next day. 1.Received an estimate in June 20, 2022. 2.Contacted Sandy, by phone asking questions about the estimate 3. Sandy tried to get Joe the guy who did the estimate to contact me. He would never call me back. 4. Joe finally contacted me because I wanted an estimate for gutters. 5. June 24 I emailed and called because I had not received a call back from Joe. 6. June 24 I shared my frustration by phone to Sandy 7. July 18 was when I received the updated email with gutter estimate; mailed check for the Hardie installation 8. July 28 they cashed the check 9. Heard nothing from this company even after paying a deposit for my work to be done. 10. August 1 emailed Sandy my frustration with this company. 11. Fred GRENNAN decided to call and say he would handle my project concerns; he never did. 12. I had to call this company weekly to get updates on what they were going to do about my project; the bad part is they wouldn't respond 13. Heard nothing from this company in late August or in September 14. October 10 called Fred no response 15. October 10 called Hardie to complain about Grennan 16. Got a call from Jason October 17 telling me he would be starting my job Tuesday October 18 17. October 18- Jason texted this "Thank you good morning to you I picked up all the material for your home this morning but they are calling for rain today so I will not be able to make it down till tomorrow morning but I'll see you tomorrow morning sorry about any inconvenience" 18. October 19- came and left his trailer and said this he was having truck problems 19. October 20- called and said his transmission went out and he wasn't coming; would come tomorrow and do an excellent job 20. October 21-came at 9:30am and started the job; torn out the old material; put Hardie up 21. October 22-came at 10:30 by himself began finishing up project; painted; I cleaned up 22. October 23- came and caulked and touched up No one should have to go through all this to get a job done. I don't know if it was because I'm located in Detroit or what. This company made me feel like my job wasn't important to them. read more

We hired Grennan Construction to fix a leak in our roof and were told the source of our leak was the metal ridge vent and that it needed to be replaced. We were given a price and told them to go ahead and do the repair for the leak in the roof. Shortly after that it leaked again so the salesman came out and said it was nothing to do with them and that they fulfilled their agreement, refusing to correct their misdiagnosis of the leaky roof. Grennan Construction replaced the metal ridge vent with plastic and fixed the drywall damage inside the home in the second bedroom's ceiling. When it leaked again it was in the exact same place as before the repair and the drywall they fixed was now worse than before. It appeared to us that the ridge vent was not the problem so we called another contractor to come out and look at the roof and he said it was leaking because the shingles were installed wrong because they used the racking method to install dimensional shingles. The root cause of the leak was that our roof has two layers of shingles on it and the first layer had simply rotted away from leaks as well as the fact that here was no felt or ice shield on our roof. This proves the misdiagnosis by Grennan Construction as well as selling improper equipment. The new contractor said we needed to replace our roof that was the only way to fix it properly. He also noted we had one soffit vent on the home and the ridge vent that was installed required soffit vents to work properly. During heavy downpours of rain, there are zero leaks in my home due to the proper roof repair by the new contractor. Please stay away from this company as they will not honor their commitments to fix your problem and their lack of expertise in diagnosing problems with your home is alarming. read more

I cannot say enough great things about Grennan Construction. I had heard wonderful things about this company, and hired them to do my parents roof 5 years ago, when they needed a new roof. I was so impressed with the workmanship, professionalism, and kindness this company and their crew showed us, that I hired them to do my own roof. So, today November 5, 2016, it was my turn and they came out (on a Saturday no less) and did a complete tear off and replaced our roof. They worked from morning until mid evening and the clean up was impeccable! I cannot thank Terry, Adam and Derrick enough for such a pleasant and professional experience. Grennan is very lucky to have them on their team. I didn't catch the names of all of the guys up on the roof but they were equally terrific and hard working. They were so respectful of our plants and bushes as well. Grennan Construction, I will recommend you to anyone I know needing work done on their home! Thank you bunches! read more