Water leak and rust issues on RSF onyx fireplace

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Mar 4, 2021

Just recently I have become aware that I have rusting going on in various issues in my 13 year old onyx fireplace by RSF-ICC chimneys. Unfortunately at the moment the soonest I can get someone to come down to inspect the unit is late October. This is a concern to me because We use this fireplace to heat from november all the way into march, and if there is serious damage I don't know how long that whole process would take with insurance and other things. So a few years ago I noticed a little dripping down the face of the unit, I didn't think much of it as we hadn't used it that winter and that season was extremely cold and snowy, so i figured maybe it was just frost or condensation from it becoming milder out. Then about a couple years later when cleaning the unit I noticed a bit of rust rust behind the top louver at the base of the flue, but everything else seemed fine. Then this year I found out the shingle work around the chimney on the roof was done fairly poorly, and the inspector noticed moisture around the edge of the chase, as well as a dip in the chimney chase cap, most likely caused by the roofers putting their tools on it and bending it. So far the rust looks like it has spread and water must have leaked to the bottom because the floor of the fireplace has a lot of rust visible too. Last week I checked around the top of the flue ( third image to the right ) and noticed a tiny bit of water on my finger tip when feeling around. This is where I figure the water must have gotten in from, So I am also worried about the condition on the outside of the unit, particularly the top where the chimney connects. We used the fireplace all last winter with no issue, and that was before we realized how bad the rusting / water leak was. I will include pictures that will showcase everything. Is this rust isn't anything major could it also still be a health hazard? The fan does circulate air around the inside with all that rust present. I know there isn't much to go by but if anyone has had similar issues or experience with this could give their opinion I would appreciate it. I don't know if my insurance will even cover the potential damage, So in that case the fireplace would be out of commission until I can afford to replace it, but hopefully it won't come to that!


20220720_145730.jpg 20220720_145849.jpg 20220827_132306.jpg 20220827_132317.jpg 20220827_132344.jpg 20220827_132502.jpg 20220827_132242.jpg 20220827_132325.jpg 20220827_132242.jpg
Last edited:
The first thing is to stop any leakage. Did the inspector provide pictures of the chase cap and the chimney flashing?

If the cabinet top is still solid and the rust is surface, then wire brushing + steel wool to move the rust, cleaning, and then painting with a high-temp paint may stop the damage.

The fireplace floor makes me wonder if there also has been summer condensation drippage inside the fireplace.
He did take pictures but Ive yet to receive them. Once I get them I will post as soon as possible. There was surface rust on the cap and a slight dip in the middle near the chimney itself I believe he told me. Unfortunately the last roofer did a terrible job when it came to workmanship and it wasn't done right or sealed properly around the chase / roof area, and it was a bit wet when he checked. I assume that is where some of the water came in also. But a lot of it looks like just surface rust which I know is easily repairable, but i'm mostly concerned about the top of the unit around the chimney, my adjuster is trying to get someone to look at it sooner but its been difficult finding anyone.
The chase cap should have been made of stainless, but hopefully the rusting is not too serious and can be stopped. Does the cap have a raised flange or lip where the chimney pipe goes through or just a hole in the flat plate?
Yes, and I just received these photos. In his letter he wrote that the chimney flashing is holding shingles up in valley, Chimney chase saddle valleys are cut too tight and have joints and nails too close to the valley. Water has been running under the valleys. Chimney chase top is bent down and is pooling around pipe.

Water leak and rust issues on RSF onyx fireplace Water leak and rust issues on RSF onyx fireplace Water leak and rust issues on RSF onyx fireplace
That's not great. Could be multiple issues. If there is no raised rim on the chase cap then they may have been depending on the silicone to do all the sealing at the storm collar.