Expert: Bruce E. Johnson - 2/25/2010

Question
QUESTION: I have recently purchased a late 19th century Castle outside Damville France. It is a 4 story structure with a 5th floor attic. It has 12" thick Flemish Bond Brick walls with cast stone bands, corbels, window and door frames and dental mold. Typical Gothic features. I am wanting to restore a 44x24 wing of the residence to the 21st century, from the existing floor of the 2nd floor to the ceiling of the 4th floor. By gutting the inside of this area am I going to be compromising the structure of the outside brick walls by removing the floor of the 3rd and 4th floors and building a stud walls against the brick to support the the new ILEVEL floor joist system and to install new electical and insulation? Also how do you support the above wall while cutting a new 6 foot opening for a new double door entry? And how best to replace deterorating cast stone corbels/dental mold features without removing 15 courses or brick above. Pictures available of infected areas.

ANSWER: Hi Jim, every structural renovation of this building will have its own unique problems.  To be very basic sight unseen, you will need to brace the walls using standard masonry braces available from most masonry supply companies.  By using these steel braces inside and out you stabilize the walls as you remove and replace the various elements.  Since it is four stories you may need a structural scaffold erected on the exterior and tied into the existing walls.

If I were doing this project? I would probably start on the first floor, brace the walls, remove and replace the floor system and then continue to the next level using the new floor system to support the bracing for each consecutive level.  This method requires a simple scaffold on the interior at the bracing points.  As far as cutting the doorway? Most masonry and stone buildings with corbels and precast elements are fairly self supporting.  I am presently doing a remodel on a Cathedral and have to cut large openings in brick/masonry walls topped with precast stones..and the transitional beams between levels support the upper weight so that the masonry below is only filling a void.  Of course this is up to a point.  
When you get over two meters or seven feet then additional structural support may be needed.  The beauty of masonry is that if you have enough mass on each side of an opening the header or lintel above the opening will not collapse.  In order for masonry to collapse there has to be lateral movement.  If you have ever picked up three wooden blocks you know that by applying pressure to each side of the middle block with the two outside blocks, the middle block won't fall.  Masonry that has been in place for any length of time has become for lack of better words, solid.  By using concrete chain saws and proper cutting equipment you can cut out and remove any element.  Once the element has been removed and is recast. It is ready to be replaced.  It is slid into place, shimmed inside the opening and then mortar is pumped into the joints.

I love this kind of stuff I could go on and on..but seriously, you need to enlist a structural engineer to work up a shoring detail based on your requirements. I hope  this information helps please feel free to write again sincerely bruce e johnson..bejohnsonconsulting.com

 

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QUESTION: Unfortunately I have to start at the ceiling of the 4th floor and work my way down due to existing load bearing walls of the 3rd and 4th floors that support the existing ceiling/floor joists. I am a bit disappointed that the 3 brick thick (12") Flemish bond walls will have to be braced, because that seems to tell me that engineer who wants this job (second one enlisted) is not as experienced as he says or is just telling me what I want to hear! I smell big change orders coming!!!!!!! Maybe it is time for a fourth bid.... You up for a two year holiday in France to over see it???? But as to you answer on the precast stone and the opening Thank you very much. I have tackled several restorations and remodels in the past and PM'ed several residential projects but never on this scale ( over 16,000 sqft) but am looking forward to the challenge. Thanks again.. I'm sure I'll be back with more.

ANSWER: Hi Jim, I'm really not sure just what you are trying to do.  Just basic interior remodeling shouldn't require shoring or bracing.  If the brick work is done properly you may not need it.  I was picturing you ripping out all the floors and leaving a 40 foot wall unbraced without the diaphragms of the floor systems to stabilize it.  But one level at a time using selective demolition and you should be fine.  I don't want to step on any engineer's toes, especially one who is on site and able to see actual structural conditions.  Any large remodel job, particularly an older building is bound to run up some unforseen expenses.  The key is to nail you contractor down as specifically as you can with no extras unless you okay them and approve the price.   Anything I can do to help, feel free to write again.  If you have photos of particular problems I would be glad to add my two cents worth..sincerely bruce e johnson..ps my wife says she loves France!  

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QUESTION: Bruce,
Thanks so much for your time it is good to discuss this with someone of your expertise. Let me try to explain it this way. Your vision of me ripping out the interior of the structure was a correct visual. Once the new roof is on, my intent was to demo the east wing of the structure, a large oblong octagon 37'x 25'(see attached highlighted area) leaving the floor of the second level in tact, and removing the 3rd and 4th floors and interior walls. The reason was this. There is a load bearing wall that is also Flemish bond brick 2 bricks thick 8" that runs straight up the the room, off center and rises to the ceiling of the 3rd floor. There are beams that run the width to this wall and then the floor joists run between the beams. But the beams sit into the exterior walls in a pocket made as the walls were erected. They are approximate 6"x10" placed side by side to make a 12"x10" doublebeam and there are three of these per floor. So if you follow me, there are 4 sections of floor joists wall to wall over the 36" span. These beams obviously sit on the off-centered loaded wall. the second floor is actually the main floor. All the major rooms are here and my intent was to open this room up giving me 900sqft of open floor for kitchen, breakfast room, and family room using 117/8 ILEVEL floor joists to clear the span. Doing the same thing on the 3rd floor for the master suite and bath. The 4th floor would have 3 bdrms and a bath above the master. Aside from a lot of masonry work and the elevator shaft going in one of the 4 turrets this is the most ambitious part of the restoration/renovation. My thinking was since the beams only sit in pockets in the exterior walls, was that these walls are pretty much self supporting and that these floors could be removed without compromising the structure. As to stepping on the toes of the engineer no one has been hired YET. Only bids from three to get the job. And I have only met with two on site to walk the site. I have copies of the original floor plans and the blueprints of the changes I wish to make. AND plenty of pictures. LOL but can only download one here. For more pics my email is  

Answer
Hi again Jim, sorry, but I've been a little busy the last couple days.  Anyways, I reread your letter a couple of time trying to visualize what you have planned.  I don't see any reason why you can't get rid of the bearing wall down the middle of the room if your new joists are capable of making the span.  Long span joists need to be bridged properly but other than that I agree, the more open a floor space can be, the better.   I tend to agree with you about the brick walls, if the beams are just sitting in pockets then the beams are not integral to the lateral bracing of those same walls. I would love to see more photos if you get the chance..I have an email link through my website.   I hope  this information helps please feel free to write again sincerely bruce e johnson..bejohnsonconsulting.com