Should I seal my subfloor?

What is a Kilz Subfloor Sealer?

Kilz is a German word meaning “small” or “little”. A kilz subfloor sealer is designed to fit into small spaces between studs.

It prevents water from seeping through the wall cavity and entering your home. The key feature of kilz subfloor sealers are their unique design which allows them to be installed with little effort and minimal time. They are designed to prevent water from seeping through the wall cavity and entering your home.

A kilz subfloor sealer is not just any old sealant; it’s a special type of waterproofing material. The reason why they’re called kilz subfloor sealers is because they use a specially treated plastic film sandwiched between two layers of drywall.

The first layer is made up of a thin layer of plasterboard, while the second consists of a thick layer of polystyrene foam (PSF). When moisture penetrates through the wall cavity, it causes the PSF to expand and cause pressure to build inside the walls. That pressure eventually leads to cracking due to increased weight.

There are many reasons why you may want to use a kilz subfloor sealer. If your house is made of wood (or any other material susceptible to moisture penetration), then it is likely to suffer from damp and mould issues.

Furthermore, water can damage electrical wiring and cause the growth of mould, which can be harmful to your health. In some instances, water actually seeps in from outside. That could be due to rainwater or groundwater, for example. Existing mould and water damage is another reason why you may want to use a kilz subfloor sealer.

Unfortunately, professional contractors may not agree with the use of a kilz subfloor sealer in your home. Some building professionals maintain that filling the wall cavity with anything other than foamcrete will reduce its thermal insulation properties.

Many people believe them simply because they’ve heard such claims before. But is it true? Or is it simply an over-hyped myth?

One of the main reasons why people believe this claim is because of thermal bridging. Thermal bridging occurs when heat travels across a part of the wall that doesn’t have insulation; it’s usually at the junctions between two different types of materials.

For example, a wooden stud (which has poor insulation) meets a steel beam (which conducts heat very well). In such cases, heat travels along the beam and enters the studs. This is a significant issue in older homes.

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In order to determine whether or not a kilz subfloor sealer causes thermal-bridging, we need to look at the science behind it. Asphalt and petroleum-based caulks are the main ingredients in traditional caulking products.

When these types of materials are installed in your walls, they can eventually become soft at room temperature (this process can take a few years). As they soften, they allow the materials around them to flex. And when the materials around them flex, it puts pressure on the studs.

In theory, applying a traditional caulking product should cause a wall to experience thermal-bridging (especially in the long-term). However, according to research published by the Department of Energy’s Oak Ridge National Laboratory (ORNL), this doesn’t actually happen.

They tested the thermal conductivity of traditional caulks, and they didn’t find a significant difference between before and after installation. This means that applying a traditional caulking product shouldn’t cause a wall to experience thermal-bridging.

Furthermore, an independent test performed by This Old House magazine also reached the same conclusion. The purpose of their test was to see how much energy could be saved by using spray foam insulation (as opposed to traditional caulking products).

They found that the spray foam did a better job than the traditional caulking products; saving homeowners an approximate of 31% on their heating and cooling bills.

As you can see, there is very little evidence to support the claim that traditional caulking products cause thermal-bridging. And when combined with the advantages of using a kilz subfloor sealer, it is easy to see why it should be considered as a more preferable choice.

Caulking products are significantly less expensive than foam insulation; especially when you take installation costs into consideration. On average, you should be able to install a bead of caulk for about $1.25.

You should be able to spray a bead of spray foam for about $5.00. That’s a big cost difference!

Furthermore, caulk is significantly easier to apply than spray foam; mainly because you don’t need a special machine and expensive training in order to do it. All you need is the ability to hold a nail gun.

This means that a homeowner doesn’t need to pay for expensive labor costs (which would drive up the price of spray foam).

As you can see, there are many advantages to using caulk instead of spray foam. Despite being less effective, it is significantly easier to apply and much more affordable.

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In addition, as we briefly mentioned earlier, you should pick out a color that closely matches the color of your brick (if applicable). If you aren’t sure about which color to choose, you should buy a small can and test it on a small area before committing to it.

Alternatively, you could pick a color that complements the color of your brick to make it look like it was originally part of the design.

Now that you have picked out the perfect color, it is time to apply it! This process is quite easy and similar to applying regular old school caulking.

Contrary to popular belief, you don’t need to completely remove all of the old caulk. In fact, you shouldn’t remove it. Not only do most caulking products seal better if there is some sort of bond to the substrate (in this case, your bricks), but removing it could potentially damage your mortar joints and brick face. This could cause even further issues down the road.

Instead, if you need to, you can simply scrape off loose bits and push the rest back into the joint. From there, you can apply your new caulk in the joint with a small caulking gun.

The application process is quite easy, so you shouldn’t have too many problems with it.

Afterwards, all you need to do is wait (although this is not recommended). We recommend waiting a full 24 hours before exposing the caulk to water; although you could get away with just a few hours before hand if you need to use your shower or bath.

There you have it folks! Now you know how to fix the ugly yellow-stained nasty looking bathtubs that are found in older homes.

While this solution may not entirely be perfect in that it doesn’t fix the underlying cause of the staining, it is certainly a suitable solution in most cases.

If you do wish to tackle the issue from the source, we recommend looking into a thiosulfate solution. You can either go about this by purchasing a presoak product at your local home improvement store or create your own mixture out of an ironite chemical (often found at swimming pool supply stores) and a bit of bleach.

We recommend using a bit of elbow grease and an old toothbrush to scrub the stains before presoaking and after; however, even the most worn and dirty stains should at least lighten up if not disappear completely with this process.

If you are uncomfortable with this method, then we highly recommend the previously mentioned method using the store-bought products.

Good luck!

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