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Can I replace masonry chimney at roofline?

gliptitudegliptitude Posts: 59Member
The chimney that my boiler vents into is deteriorating and I am debating what to do.

There appears to be a few different factors working together to destroy this chimney, from the inside and from the outside. It is brick and it is integrated with the brick wall of the house. I presume it has a ceramic liner. There are at least two chambers and I don't think either is straight. There is also a small window in the middle of the chimney.

If money were no object and if I were confident this would be my own house forever, I would certainly abandon this chimney, demolish it at the roof line and replace the boiler with a new high efficiency one. Having that chimney gone would also make it much easier to build the roof out on that back side of the house the way I think it should be, (with an overhang like is on the front of the house).

My status being what it is though, I am considering fixing this chimney and trying to figure out what's practical. If this chimney is going to be used again next winter it will need one of those metal liners installed. I'm trying to figure out if that's doable, if it's something I can do or someone else can do and if it'd be worth it.

** I'm also trying to figure out if it is possible to transition from masonry to B-vent or something metal and engineered for the purpose. **

I think it would be a lot easier and cleaner job if I could demo the chimney down to the roofline. I'd be eliminating variables and going for a streamlined design, with fewer drainage/flashing/mortar/maintenance issues and also much easier access for installing the liner. And I'd be able to build the roof out more sensibly.

I'm not sure if it's to code, if a liner might make it to code, and how the transition should work. I don't plan on being inspected but I like to prepare for it and obviously I like it to be functional and safe, if not proper.

Can it be done?

Comments

  • Jamie HallJamie Hall Posts: 10,279Member
    Without seeing photographs of the chimney, and at least an elevation of its path up from the foundation, almost any suggestion I might have as to repair would count as a WAG (Wild A$$ Guess).

    That said.

    First, the chimney -- as it stands -- is an architectural feature of the structure. Is the structure historically significant? If so, removing the chimney would harm that and, quite possibly, reduce the value of the property.

    Second, if the flues are not straight, slipping a metal liner in might be rather difficult, to put it mildly.

    Your best bet would be to locate a really reputable chimney and masonry expert in your area -- they do exist (I might add that there are a greater number of disreputable ones, so be vigilant and do your research -- and NOT on Yelp or Angie's List or some other crowd sourced site). They will be able to evaluate the condition of the chimney, inside and out, and recommend the best procedure for repair and relining, if that is possible.

    Your desire to make it functional and safe -- and to code -- is well thought out. You may or may not be inspected at the time of construction -- but you will be, if you ever try to sell the house, and if there is other damage related to the chimney or boiler venting at a later date, you can be sure the insurance people will be very interested in what was done, and how.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • gliptitudegliptitude Posts: 59Member
    Thanks for the reply.

    I know that the house is not a registered historic building and I know that it is not located within an historic district. The house already has another chimney that is abandoned and demolished to the roofline and roofed over. .. Selling this house soon is something I've looked into and would be a "rehab opportunity" "as-is" type sale and I know that almost any contractor around here would abandon this chimney and the whole hydronic system in favor of high efficiency forced air. But as the owner-occupant I am personally invested in the radiators and really couldn't even think of this place as my own without them. .. So this chimney failure is kind of a crossroads in the project and my ownership.

    I was in a similar but less urgent situation years ago with my previous building and at that time actually did discuss it with the building inspector, although the work was never done and I never got confirmation that transitioning from masonry to metal was practical. As I remember he said that a consistent run of double-walled metal pipe, like B-vent, (all the way from the appliance in the basement, up through the roof and at or beyond a certain height beyond the highest peak of the roof structure), would be the most explicit and direct way to comply with building code. He indicated that this material cannot go through the existing chimney and would have to be conceled otherwise from the living space and framed to some specifications to avoid direct contact with wood or combustibles. .. He SEEMED to indicate that the existing chimney could be retained instead and transition to a metal pipe at the top, but that that would require some difficult internal modification to the entire length of the chimney, but he wasn't really clear on what that was, if it would be an engineered system of some kind or a specified material.

    .. The second and third photos here are meant to show the difference in roof overhang in the back versus the front, which might help explain why I really want to remove the top of this chimney and improve the overall drainage of my roof and gutters. The fourth picture shows deteriorating plaster damage on the chimney inside the house, in a room that I have unfortunately quarantined and ventilated for this reason.















  • Jamie HallJamie Hall Posts: 10,279Member
    Well, of course you ca take the chimney down to the roof line. You have, however, a good deal more trouble than that: you have a lot of moisture seeping through the walls. I notice some attempts at patching -- perhaps with mortar? -- in other places on that end wall and around the corner, and a lot of deterioration of the brick.

    I doubt that you will have much luck getting a liner into the chimney; there is at least one significant offset directly over that window.

    What has happened is that for one reason or another -- and what is past is past -- the hard waterproof outer surface of the bricks has been damaged or lost.

    What needs to happen -- regardless of what you do with the chimney -- is that any paint or other finish on the brick needs to be removed, as well as the patching material -- but do not, under any condition, use sandblasting or harsh abrasives or brushes. You will ruin what little waterproof outer layer is still on the brick (probably not much, but why push it?. Then you need to apply a known, penetrating waterproofing sealer to the entire wall surface -- top to bottom.

    You will also need to be able to keep the interior of the house warm and keep the humidity at reasonable levels; ideally you would place a vapour barrier on the inside, but that's a big job.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • lchmblchmb Posts: 2,922Member
    that is a really cool chimney..just sayin
  • Bob HarperBob Harper Posts: 803Member
    That chimney is a mess. Lots of code violations. You need to get a chimney pro in there to perform a level II inspection to determine if the chimney is salvageable. It will need a listed ss chimney liner at min. If you really want to chop off the top at the ridge you can do that then cover it with a stainless steel 'chase cover'. These can be powder coated as can a Class A listed chimney or type L vent and attending fittings and cap. I just did this at my house and I'm a chimney pro. Several liner mfrs. make a listed transition plate from liner to factory chimney. The chimney regardless needs to stick up 3 feet above the roof/ 2 ft. above any part within 10 feet horizontally. I"ll try to post some pics this weekend.
    Please provide make, model, fuel, input BTU/hr. and appliance collar diameter, lateral offset from breaching and vent rise from top of appliance collar to breaching in wall (where the pipe goes in).
  • FredFred Posts: 7,814Member
    edited April 19
    It's very difficult to tell what parts of that house are original and how many modifications have been made over the years. The soffit on the second story looks to me like an early modification that wasn't properly tied into the roof and may be allowing run-off to pool and run down the brick. That is a soft brick and it will absorb water and, in the winter moisture will freeze and burst the facing off of the brick. The fact that the window caps are partially covered with that soffit is a tell tale sign that something was modified there.
    The facia boards on the rear, leading up to the chimney aren't correct either. I see there originally were two doors on the side that were taken out and replaced with windows and the lower portion bricked in. The brick infill was nicely done and it is an early modification but they left the limestone door sills and steps there.

    That full size window over that fireplace is also suspect. I'm wondering if someone didn't cut into that wall/chimney to put that window in there. The wood trim cap on that window is also different from the others and the brick arched header is not flush with the brick wall, like the other windows.

    I really think the modifications to that house created the problems you are having and I'm not sure how far you'd have to take it back to correct that problem.
  • gliptitudegliptitude Posts: 59Member
    edited April 19

    It will need a listed ss chimney liner at min. If you really want to chop off the top at the ridge you can do that then cover it with a stainless steel 'chase cover'. These can be powder coated as can a Class A listed chimney or type L vent and attending fittings and cap. I just did this at my house and I'm a chimney pro. Several liner mfrs. make a listed transition plate from liner to factory chimney. The chimney regardless needs to stick up 3 feet above the roof/ 2 ft. above any part within 10 feet horizontally. I"ll try to post some pics this weekend.

    Thank you very much. This is the information I need to start planning.

    If these engineered transitions exist and are code I fail to see why I should preserve the chimney above the roofline, where it will be a perpetual maintenance issue and immediately needs major work. The drama of demolishing a masonry chimney is minimal in my case because I have done it before, several times actually, and have a developed strategy, including safety precautions and because the circumstances of my ownership here leave me quite a bit of freedom. The advantages of having it out of the way are numerous, not the least of which is having easier access to the interior of the chimney to run the liner.

    I was considering doubling duty on a sewer snake camera rental that I wanted for my main drain line, thinking that might go more easily through my chimney than a chimney sweep and obviously more easily than a chimney liner. .. Is that something that is done to survey the inside of a chimney?


    Please provide make, model, fuel, input BTU/hr. and appliance collar diameter, lateral offset from breaching and vent rise from top of appliance collar to breaching in wall (where the pipe goes in).

    The appliance is a Dunkirk boiler, natural gas, 105,000 BTU/hr input, according to the label. I'm not sure I've got the other stuff right, perhaps these pictures help. The vent pipe coming out the top is 6" in diameter. When it enters the chimney it is slightly bigger, if that's possible. Horizontal distance from the face of the chimney to the center of the vent pipe at appliance is 4'4". Vertical difference between top of boiler to center of the hole in the chimney is 29".

    I measured the chimney itself to be 33'8" from base of the stone foundation in the basement to the top of the masonry.




    Fred said:

    I really think the modifications to that house created the problems you are having

    I agree and appreciate your narrative, but I don't think I can reasonably go back to how it originally was.

    There are other similar ridiculous things about this house that cause me to speculate on the history and sequence of modifications. As a general rule and method, my strategy is to simplify and eliminate variables, and prioritize what I see as the engineering issues. I'm at liberty to do that because it is not a historic building and my ownership is pretty clean and un-encumbered, (no mortgage, no spouse, no building inspector, no official record of code violations).

    The box gutters are a long term headache. I'm not averse to eliminating the historic features of them but I think there still needs to be an overhang (and an additional overhang on the back side of the house) and I'm not sure how to redesign it.
  • FredFred Posts: 7,814Member
    @gliptitude , if those box gutters are relatively solid (or any rot/damage is isolated enough to be repaired, you can get a rubber membrane to line the interior of them. I'm just not sure they are a part of the original design of the house. They are out of scale and not integrated into the roof edge like one would typically expect.

    Also consider having that step flashing that goes up the roof line on the one story section of the house and lays against that back wall replaced. It was installed incorrectly and is a part of your water infiltration/ brick face problem. That step flashing should be installed so that each step (on the roof) lays directly under each shingle so as to prevent water from running under it. As it is installed (at least from what I can see in the pictures), it looks like the roof side of the flashing either lays on top of the shingle or maybe even an inch above the shingle, allowing run-off to flow under it and against the wall and probably down the inside of the one story section.

    There are many, many mysteries with the construction and changes that have occurred on that house. From the look of the front porch and the short, out of scale second floor windows, it almost looks like that house started its life as a one story cottage or what we call a "shot gun" (long and narrow one story) and, at some point, had a second story added. During the timeframe of the construction of that house, it wasn't uncommon to build what was called a "half house" where, for financial reasons, they would build half of the house that was planned with the intent to later add the second half.

    A chimney, like that is typical of a Federal style home but if it were, an identical chimney would typically be on the opposite end of the house. I'd love to know the history of that house!
    Oh well, you didn't come here for a conversation on historic construction/design. Sorry.
  • Jamie HallJamie Hall Posts: 10,279Member
    As I noted in my earlier post, the chimney and its idiosyncracies and the gutters and theirs are among the least of your worries. You have real problems with all the brick, as I noted, and whatever you do you need to address those problems.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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