remodels Renovations and adaptive reuse of older buildings are becoming more and more common nowadays due to accommodation of factors remodeling or renovating an existing building especially an older building may seem simpler than building from scratch however upgrading these existing homes poses significant challenges especially when it comes to insulating we're seeing a massive push from the industry to reduce energy consumption and to improve Energy Efficiency with a plethora of programs and code requirements probably for the right reasons even outside of the code requirements and local ordinances no one wants to live in an uncomfortable home whether you're dealing with cold air drafts or overheating during the summertime not to mention you have to pay for all the excess heating and air conditioning however insulating without addressing moisture can lead to the rapid deterioration of the existing building as insulation slows heat flow which means that the drying potential is reduced as less overall heat is passing through the building heat is required for drying to occur for example in the hot humid South insulating building reduces the loads on the air conditioning system the incident dehumidification benefits provided by the air conditioning system are now essentially eliminated since the air conditioning isn't running as often that translates to less heat flow across the building now this results in higher interior relative humidity levels as the conditioned spaces still remain cool which places the interior surfaces at a much higher condensation risk which can sustain mold growth and rot the presence of insulation impacts almost every part of the building I happen to like giving old buildings a new life making them more energy efficient and preserving them for future Generations but has to be done correctly if the goal is Preservation and sustainability there's nothing more sustainable than a building that lasts a long time and is used continuously but durability has to be high on the priority list for that to happen and in some cases this means not insulating the building new buildings have a lot of benefits for one we have complete control of how the building is designed and we have a pretty good idea of how it will perform from a moisture perspective a thermal perspective and a structural perspective relative to The Climate we're building in and the site's stipulations we know how to limit rainwater penetration we know how to air seal and insulate properly to ensure long-term durability of the structure this is easy because it's predictable however working with an existing building can sometimes be like going in blind we can't assume anything about the building until we've actually confirmed what's there since Decades of Maintenance repairs and deviations from the plans have an enormous impact on how the building performs because older buildings were poorly insulated or completely lacked insulation small leaks and condensation weren't really a big deal since water dried out quickly from the Abundant amount of heat flowing through the building old growth Lumber also had a greater potential to absorb water and higher resin content to resist mold and fungal growth now these small leaks are often hidden or obscured from view until the building is insulated suddenly you might start to notice wet spots on the wall or around window openings or musty smells you might start to see mold growing on the walls or the ceilings or the paint starting to fall off of your sighting remember less heat flowing through the building means that the building dries slower the more you insulate the better you have to be about managing bulk water and moisture and air leakage you tend to see a lot of problems in older homes that have been retrofitted with blown in cavity insulation using a less invasive method of insulating where small holes are cut into the wall cavity and filled with blown in cellulose fiberglass or mineral wool and then the attic is filled with that same blown in insulation material this is a cheap and easy way to insulate that doesn't impact the inhabitants of the home and you can get a fairly high performance out of such a simple insulation method unfortunately you don't get the benefit of examining the condition of the backside of the sheathing or the stud cavities often times you'll see evidence of continuous water staining and condensation if you're able to access the interior stud cavities and this is even more prevalent around window sills and punched openings if you go to insulate these locations haphazardly by blindly pumping insulation into the stud cavities the walls are probably going to rot out relatively quickly some very old homes and buildings didn't have sheathing or weather resistive barriers and these types of wall conditions are at an even higher risk of moisture issues since they're inevit getting wet more often properly insulating these high-risk walls can be tricky and downright impossible at times depending on the building conditions and the limitations of the project scope the budget and the local historic ordinances old wooden buildings with stucco facades are at an even higher risk of deterioration if they're insulated as stucco is a reservoir clading that's essentially bonded to the wood framing or if you're lucky separated by a couple layers of tar paper and acting as a sponge by absorbing rainwater and distributing it to the interior framing behind it the old growth l Lumber that was often used to frame these types of walls could handle the higher moisture content since they have the ability to dry out but there's just no good way to insulate these types of walls without removing the existing stucco and providing a drainage plane same thing with vented crawl spaces vented crawl spaces weren't an issue until we started insulating them in cold climates the crawl spaces became colder since heat flow into the crawl space was reduced and the incoming air condenses on the underside of the wood joists rotting them out over time poor air flow in these vented crawl spaces only increases relative humidity worsening the problem in hot humid climates where we use a lot of air conditioning insulating keeps the temperature of the subfloor colder and the warm humid air entering the crawl space condenses on the underside of the cold subfloor and we get subfloor rot and joist Rod now we know that if we have a crawl space it must be designed as a conditioned crawl space or the framing must be contained within the conditioned space above the vented crawl space and sealed off to prevent any moisture migration insulating old addicts also poses a similar issue especially in cold climate and humid climates haphazardly insulating a vented attic without air sealing the ceiling plane often results in mold growth and rot at the location of the air leaks such as around recess lighting penetrations exhaust fans and other holes we talked about this in another video which I'll link up here air leakage has the potential to transport moisture at a rate that is orders of magnitude higher than diffusion alone and when that warm moist air from the interior comes into contact with a cold surface we get condensation which is a perfect Catalyst for mold growth perhaps one of the biggest reason reasons not to insulate is if you're working with an old Mass masonry wall these types of buildings are made up of several thick layers or whs of solid masonry or sometimes not completely solid and are designed to manage rainwater penetration through storage rather than exclusion or drainage the wall is designed to store and redistribute water as masonry has the potential to absorb and store a lot of moisture improperly insulating these types of walls have detrimental effects remember insulating reduces the drawing potential of the walls and there therefore the walls stay wetter for longer if masonry walls are wet during freezing temperatures water has the potential to freeze within the masonry leaving behind concentrations of salts which can result in subf fluoresence and spalling which is essentially the structural deterioration of the brick where it literally falls off embedded wood components in the masonry also rot out at the embedded ends because they're staying wetter and colder and heat flow can't dry out those joist Pockets quickly enough and any leaks through cracks and gaps in the masonry wall or at window penetrations has the potential to rot out the interior Framing and sustain mold growth on the backside of any interior finishes using the wrong type of insulation can also trap moisture at the interface between the mass wall and the interior framing so a lot can go wrong by insulating an old Mass masonry wall we also discussed how to insulate old Mass masonry walls in another video which I'll link up here as well in all these cases I described here we need to be asking the question as to whether insulating is an appropriate option given the existing conditions the budget and any other project limitations logistical or otherwise in almost every example that I gave we have options that can work and allow you to insulate properly while maintaining the long-term durability of the structure not all of them are cheap options by any means but they are necessary when dealing with existing building conditions insulating improperly can do more harm than good and we need to be very cautious about not making things worse than they already are old buildings have lasted as long as they have for a reason and even good intentions can have bad consequences so sometimes it's better not to insulate if we can't do properly if you're looking for a complete guide on how to remodel your old home properly get my moisture management guides residential remodels where we discuss how to control moisture and safely insulate a wide range of existing building conditions that's only available at A-D designs.com sshop links will be in the description below we've also got over 150 free building science articles many of which cover topics that we discussed in this video except at even greater depth make sure to give this video a like if you haven't already and subscribe for more weekly building science content for now good luck with your project cheers [Music]