What is an engineering letter? An engineering letter is a letter, by an engineer or architect that is acceptable to the building inspector, which gives instruction for correcting (fix) a structural defect noticed during the building process.
I have noted of late that many of the searches Owner Builder Online gets are questions about fixes. The searcher wants to know, “ Can I dig under my slab?”, “ How do I fix a leak under my slab?”, etc.? These questions suggest that something was forgotten or broken under the slab and, guess what, we are probably going to compromise the foundation to fix it.
Fixing a problem under the slab is not out of the question. Sometimes it is a requirement. The owner builder cannot leave a leak underneath their slab. What can be done? The plumber must locate and mark the leak. They will use a snake camera to do this. The concrete contractor will remove a section of the slab. The area below the slab will be dug up and the pipe fixed.
Now…here’s the catch. The owner builder will have to go to their architect, present the situation and get an engineering letter, detailing how the slab will be fixed. It must be stamped. With the pipes still exposed, a general inspection should be called. The building inspector will verify that the waste line has been fixed and there is no leak underneath the slab. Find out if the compaction will need inspection before the final pre-pour inspection. If it is, mark it down and don’t forget.
This same procedure should be followed for any concrete foundation fixes.
It is normally the case that dowels or rebar will be epoxied into existing concrete to strengthen the cold joint at the fix. In Las Vegas, it is a requirement that this be done under the watchful eye of an inspector and is referred to as an “epoxy” inspection. You can normally combine that with your pre pour inspection. Be certain that all rebar and/or dowels are placed according to the “engineering letter” specifications. Have the stamped letter to give to the inspector when he or she arrives. Once the inspection is passed, the concrete can be poured back and the fix is complete. For more information on preparing the concrete slab, visit our concrete page.
Trusses are a critical element to the building. They are individually engineered to support specific loads. Any compromise of the integrity of the truss constitutes a need for an “engineered” fix. This is usually identified during the sheet and shear inspection. The building inspector will inspect each truss individually to ensure proper location and type. This will be done by comparing the sealed truss calcs to the installation.
At the time of the truss inspections the trusses are also examined to determine if there are any damaged trusses. Damaged trusses require a stamped fix, drawn up by the truss engineer or architect. The fix must be completed and a copy of the letter needs to be onsite for the inspector to review when they return.
Note that in some jurisdictions the truss inspection is a separate inspection, while in others it constitutes a portion of the sheet and shear inspection.
During the framing sheet and shear inspection, the building inspector may identify other areas of framing that do not meet either building codes OR the blueprint specifications. For instance, a header that is installed is less than what is required by the blueprints. The inspector may require that a completely new header be installed or they may require an engineered fix. That is, they may allow the engineer to design a fix. This may include raising the header and adding a 2X4. It is important that the fix matches what is in the engineering letter.
Avoid Costly Delays, Be Proactive
In all cases where an engineered fix is completed, a re-inspection must be called. Remember, while this is likely to happen, it is better to get it right the first time. The letter will cost an additional fee, perhaps $200.00 AND it may take several days to be completed. Each time an engineering letter is necessary, it holds up the project. Be proactive. Avoid waiting for an inspection to address a correction that obviously needs an engineering letter. That way, while you had to pay for the letter, it won’t hold up the job.