now if you can't excavate to access the exterior Foundation walls to install a new waterproofing layer and provide drainage you can address water and drainage on the interior so if we zoom into this detail you can see that we have a taped dimple mat membrane here installed directly against the interior side of the mass masonry Foundation walls so this taped dimple mat provides a drainage space and a capillary brake behind the masonry walls and we're terminating it over a new interior drainage tile that's set in a crushed stone bed and wrapped with Filter Fabric the drainage tile gets discharged to a couple of sump pumps with back batteries and we're relying on the system to drain out any water that leaks through cracks and gaps in those masonry Foundation walls so the dimpl mat is providing a drainage plane and a capillary brake and it serves as our waterproofing when the seams are taped and it's also serving as a vapor barrier now this function as a vapor barrier is actually beneficial if we're letting water pass through because we can get efflorescence on the interior of these masonry walls if water is allowed to evaporate and what can happen is that this can actually start to damage the masonry walls over time water passing through the walls carries dissolved salts whether it's drying it out of the mortars or from minerals in the adjacent soils and then the water dries the interior through evaporation leaving behind the salts in concentrated deposits then water flowing through the walls wants to rush to dilute those salt deposits bringing with it even more salts after it evaporates and we get these large salt concentrations which we see as efflorescent which is that chalky white substance that you will sometimes see on Old masonry and stone buildings even on concrete basement walls now if too much salt is allowed to build up on and inside the masonry which is called subf fluorescent we actually build up a lot of osmotic pressures because water wants to rush to dilute it and those osmotic pressures can actually exert a lot of force onto the brick and masonry which means that we start to get spalling where pieces of the salt Laden brick and mortar fall off which can easily turn into a structural issue so by providing this dimple mat which is an incidental Vapor Barrier we are preventing evaporation but we're promoting drainage so relative humidity remains around 100% in this Gap here preventing drying and therefore preventing efflorescence and spalling so it's okay if our masonry walls get wet as long as that water can drain out and then we don't get the efflorescence or spawing that could actually damage the wall so this is a big deal then we patched the concrete slab that we partially excavated to install the drainage tile and install a fluid applied epoxy Vapor Barrier across the entire slab to prevent liquid water and vapor from migrating inside as well as radon and then we're free to insulate the walls in whatever way we want and this particular detail we're calling out closed cell polyurethane spray foam as it has a high R value per inch and provides the benefits of an air barrier Vapor retarder preventing condensation on the surface of the dimple map we're also installing some mineral W bat insulation between the 2x4 framing for some additional thermal resistance but the point is that the dimple mat allows for a lot more flexibility in the design and the type of insallation that we can specify and then we have our standard gypson board or other interior finishes you can find more details about this solution in my most recent book a guide to moisture management for residential remodels where we discuss a wide range of solutions that work for a lot of different building conditions including old basement and Foundation walls like these old wood framing above grade masonry crawl spaces and slabs roofs windows and much more linked to the ebook will be in the description below now on the exterior we want to correct the grading so that it's sloped away from the foundation walls again we want to limit the amount of surface water that's allowed to get inside if possible we want to install a new French drain system around the perimeter of the foundation near the surface it's not installed all the way down to the footings but it's allowing any water that happens to get around the foundation to drain out before it has a chance to get inside and then we want to cap the French drain with either impervious pavers or an impermeable soil cap and that just directs water away from the foundation walls it's not always possible but this is preferable if you can't install a perimeter drain on the exterior footings this is especially important in cold climates where we get freeze th Cycles as we don't want water to freeze within the masonry walls and leave behind those salt deposits since that can lead to efflorescence sub fluoresence and spalling here we have a similar detail with our stone foundation again we have that taped dimple mat membrane that's installed against the interior of the stone walls that gets drained over a new perimeter drain tile set in crushed stone and wrapped in Filter Fabric and drain to a series of sump pumps with backup batteries we patch the excavated portion of the concrete slab and apply our epoxy Vapor Barrier over the surface of the slab to prevent moisture from wicking up and causing issues then we're sloping the grade away from those Rubble Foundation walls providing those concrete pavers or an impervious soil cap to direct water away from the foundation and installing the French drain system to collect any water that happens to drain underneath here before it has a chance to reach the foundation and we are draining that to Daylight or to a dedicated on-site storm water facility for more information on waterproofing and insulating older existing buildings head over to sird designs.com where we have over 150 free building science articles that cover a wide range of topics and make sure to pick up a moisture management guide to residential remodels this is really important stuff that everyone should know prior to starting any remodel or renovation project for now good luck with your projects cheers