{"id":741,"date":"2014-03-17T14:33:18","date_gmt":"2014-03-17T14:33:18","guid":{"rendered":"http:\/\/bathursthandyman.ca\/?p=741"},"modified":"2014-03-17T14:33:18","modified_gmt":"2014-03-17T14:33:18","slug":"typar-vs-tyvek-sbpo-window-installation-application","status":"publish","type":"post","link":"https:\/\/buildingology.com\/?p=741","title":{"rendered":"Typar vs Tyvek SBPO: Window installation application"},"content":{"rendered":"
\"IMG_3619a\"<\/a>
Two window openings using Tyvek Homewrap as the weather resistive barrier.\u00a0 At this stage, the weather resistive barrier was just installed, but not taped completely.\u00a0 This window uses a custom made sill pan out out of flashing tape and a 1\/8″ thick closed cell gasket.<\/figcaption><\/figure>\n

 <\/p>\n

These are the two of the most commonly available house wraps available at your big box stores. Although both products are weather resistive barriers (WRB) made from spun bonded-polyolefin method (SBPO),\u00a0 they have a slightly different construction, and therefore different considerations when choosing your house wrap for window openings.\u00a0 There are various types of WRBs which include different features to help you make your choice, but there are also some unpublished or unspoken qualities which make one product better than the other for a particular window installation application, and we will examine these qualities in this article.<\/p>\n

The technical background<\/h2>\n

Tyvek homewrap, made by DuPont:<\/strong><\/h3>\n

Polyethylene fibers are fuzed together to form a single material layer membrane.<\/p>\n

Permanence:\u00a0 Canada: PERM rating of 30 (1720 ng\/Pa S m2<\/small><\/sup>)\u00a0 United States:\u00a0 PERM rating of 58 (3320 ng\/Pa S m2<\/small><\/sup>). \u00a0 4 months UV exposure max<\/p>\n

Can easily break down if your siding or window frames are made with cedar as surfactants are released from the surface and break down the Tyvek material.<\/p>\n

This product made by Dupont is the most well known brand name and will charge a premium to use their products.<\/p>\n

Typar housewrap, by Polymer Group Inc<\/strong><\/h3>\n

Two layer polypropylene fibers with a surface film<\/p>\n

Permanence:\u00a0 PERM rating of 11.7 (670 ng\/Pa S m2<\/small><\/sup>). 6 months UV exposure max<\/p>\n

Surfactant and UV resistance, but by how much?<\/p>\n

Permanence<\/h2>\n

I should note, that the real ideal permanence rating depends on the rest of the building enclosure components, indented application, location and weather.\u00a0 In trade literature, both companies claim that their product lies within the ideal performance range.\u00a0 I would like to cut through the marketing to give you the truth.<\/p>\n

In theory, the highest permanence material in a cold climate should be ideal, in this case Tyvek.\u00a0 The reason for this is that the WRB is not a primary vapour diffusion control layer, so the least amount of moisture control you induce is the best choice.\u00a0 But in many cases, when I hygrothermally simulated walls in a computer program in various projects, I found the difference of moisture in a wall is usually negligible between the two.\u00a0 In a standard wood framed home with drained and vented cladding, either product will work fine.\u00a0 It is when your building enclosure is slightly different to the norm such as superinsulation, or other non-wood frame buildings is where these numbers seem to matter more.\u00a0 Although I would use Tyvek given the choice, Typar is just as acceptable for our window.<\/p>\n

Advantage: Either WRB (depending on application)<\/p>\n

Building codes and cedar surfactant release<\/h2>\n

In some jurisdictions treated lumber is required for window sills.\u00a0 Something I personally think needs to be refined as the lumber frame is neither exclusivity interior or exterior components.\u00a0 Many pressure treated lumber products such as the standard, cheapest ACQ (yellow\/green stuff) should never be used indoors.\u00a0 It can have a negative impact on indoor air quality.\u00a0 So you may think, what are my alternatives?\u00a0 Cedar is the first wood that comes to mind, expensive but easily attainable and okay to use indoors.\u00a0 The big draw back is that it can eat away at your WRB due to a chemical incompatibility.\u00a0 Typar advertises that it has resistance to this effect.\u00a0 How well that resistance performs, I don’t know.\u00a0 There are many other wood treatment companies on the market that are made with environmentally sensitivity in mind such as Timbor or MicroPro Sienna, or heat treated lumber.\u00a0 In the old days, people used to paint the frames with white alkyd paint.\u00a0 It seemed to work well.<\/p>\n

Are you using cedar shims to level your window?\u00a0 That is chemically incompatible with your SBPO. \u00a0 Time to switch to a composite shim or setting blocks.<\/p>\n

Advantage: Either (Typar in special applications)<\/p>\n

Folding memory and tear strength of WRB<\/h2>\n

One quality in which Tyvek has a disadvantage over Typar, is that Tyvek has folding\u00a0 memory.\u00a0 What I mean by this, is during the normal process of install the membranes are always folded back and forth before they reach their final position, especially on a windy day.\u00a0 The final result, is that the Tyvek Homewrap material can begin to resemble a crumpled up piece of paper.\u00a0 Now try to picture using that crumpled up Tyvek and pulling it taught to achieve uniform adhesion when taping joints.\u00a0 It is difficult to do so and takes up a lot more time to try and get it right.\u00a0 Most contractors use staples to adhere WRBs to the substrate.\u00a0 These stapes create holes in your new membrane, and I did see that the Typar definitely had better tear resistance which can potentially reduce driving rain to the interior.\u00a0 The Tyvek staples tended to cut the WRB more and create larger holes in your drainage plane.\u00a0 Not so good.\u00a0 If you use different fasteners with a gasket or flash tape each staple (PITA) and a little OCD.\u00a0 This is one of the biggest issues with Tyvek.\u00a0 For this reason, Typar was preferred by my local window installer.<\/p>\n

Advantage :Typar<\/p>\n

Flashing your WRB<\/h2>\n

This quality is probably the most important category in this article.\u00a0 If your sheets of WRB do not adhere well together, and don’t terminate well to other building materials, your WRB effectiveness is severely reduced.<\/p>\n

If you are using flashing tape provided by your WRB manufacturer or Tuck Tape, the adhesive layer is really thin, and doesn’t have the best long term adhesion properties. Tyvek is a relatively flat uniform surface, where Typar is a little bit bumpy.\u00a0 This bumpy layer makes it difficult to get good adhesion with the tape.\u00a0 If you don’t use a j-roller or aggressively push down the tape on the tyvek, uniform adhesion coupled with a thin adhesive layer can encourage water to way-find its way through the joint.\u00a0 Since Tyvek is more flat, it is easier to get a better bond.\u00a0 With these tapes, it is sometimes possible to lift up the tape to reposition it on Tyvek, Sometimes a few fibers will break and can be okay as long as it is covered with a new piece of tape.\u00a0 But with typar, the white finishing layer rips off much easier.<\/p>\n

This whole problem of flashing tapes can be solved by using a better quality flashing tape with a thicker adhesion layer.\u00a0 3M 8067 \/ 3M3015 flashing tape or some made by SIGA, Tescon, or Vycor can solve these issues with an added expense.\u00a0 I would say that in window and door openings when using WRB, these tapes are a must, where the rest of the house, you can get away with tuck tape if it is applied with care.<\/p>\n

Advantage:\u00a0 Tyvek (using manufactured supplied or Tuck tape)<\/p>\n

Chemical compatibility with sealants under the flange<\/h2>\n

Knowing that VOCs can cause issues with WRBs, I made the assumption that a low-voc content polyurethane would work better than one with a higher content.\u00a0 I called the manufacture of the sealant who’s technical person said to me that they were compatible.\u00a0 This information was good enough for me at the time.\u00a0\u00a0 They were not!\u00a0 Lesson learned, always do a test bead and let it set for a few days on your WRB.\u00a0 Chemically incompatible materials will never set properly and can become mushy.\u00a0 On the reinstall, I used DOW Corning 758 which is a silicone specifically made for compatibility with WRB, foams and plastics.<\/p>\n

Sill pan<\/h2>\n

There are many different ways to flash a sill, including flex wrap products, self-adhered membranes, tapes, and plastic pans.\u00a0 A WRB is not a sill pan material as standing water can get through (over time).<\/p>\n

Update:<\/h1>\n

Here is an interesting test done my Matt Risinger for JLConline, showing other budget housewraps with pin perforations.\u00a0 The results are dramatic, but scientifically questionable.\u00a0 In the example in the video, the weight of a glass of water on the membrane could represent a material that is close to fully adhered.\u00a0 In a real world scenario an airspace would not trap water like a piece of glass would.\u00a0 The amount of time the water is in contact with that barrier would be less as the water drains to the ground..\u00a0 If this test was to test an air space behind cladding, the results would be different.\u00a0 Most importantly, this test only proves that these SBPO materials are not meant to be used as a sill pan material which the glass jar test emulates.\u00a0\u00a0 Dupont makes a SBPO specifically for a stucco application which could imply that his test really tells us that budget housewraps are not meant for stucco.<\/p>\n

http:\/\/www.jlconline.com\/building-envelope\/is-tyvek-worth-the-price-_o.aspx?dfpzone=general&utm_source=newsletter&utm_content=jump&utm_medium=email&utm_campaign=JLCNL_051514&day=2014-05-15<\/p>\n

\"Buildingology<\/a><\/p>\n