Category Archives: covering information

Installing Multiple Covers into One Wirelock Channel

This post covers another one of our most frequently asked questions,

HOW TO INSTALL MULTIPLE COVERS INTO ONE WIRELOCK CHANNEL!

We hope the description and video can help clarify this issue a bit more. Thanks for your feedback!

The beauty of wirelock is its ability to hold multiple layers of covers, even covers in different directions (i.e. roof and ends or 2 long lengths).

Before starting you must at least have the cover tacked at the opposite end. This will give you resistance for pulling the cover tight.

Our wirelock channel will hold up to 3 layers of 6 mil plastic securely.

Two layers of 12 mil tarp will not be held securely in the wirelock channel. This is why we recommend that the top of the end wall tarp be sandwiched between the channel and the hoop.

If you have never installed these covers before, it is recommended to use at least 3 people.

  • After the bottom of the end cover has been secured, pull the end cover over the hoop first.
  • Person “A” will hold it from the inside of the structure in such a way that there are no wrinkles.
  • The roof cover can now go over the channel as well.
  • Person “B” will pull on the roof cover while person “C” installs the stainless spring steel wire inserts.
  • “C” will start from the peak and work down.

It is critical to remember that “A” and “B”, who are pulling on the two respective covers, must always be pulling at least a foot ahead of “C” who is installing the wire insert. This will allow a little give in the covers so that there will not be damage.

With more experience “B” and “C” can be done by one person.

It is also important to remember the wrist technique for installing the wire insert. Do not slide the wire straight back and forth. This causes abrasions on the cover.

As you move back and forth, apply pressure with the thumb on the next parallel spot of the wire insert.
Use a needle nose pliers to get the last tip into the channel.
The next wire insert does not have to be overlapped.

For more details and to watch an illustration, please see our YouTube Video below

Roll Up Side Wall Considerations

Ventilation can either be done passively through openings or mechanically with fans. Roll up sides are an economical way of getting lots of air movement since no electricity is required. Roll up sides become even more effective when used on longer buildings. Roll up sidewalls are often used in combination with a small exhaust fan for early and late season ventilation when opening the sides is not practical.

If a structure is very exposed, it is best not to open more then 3’ in height due to potential of wind damage. If a structure is extremely sheltered, it is best to go even up to 6’ to create maximum opening. Roll up sidewalls are most effective when used in combination with peak end wall vents to create a “chimney effect” to draw warm air out of the building, especially when it is very calm. These vents are effective for air movement when outside temperature does not allow opening of the sides.

When a structure has a low profile, you will need to be careful during rainy periods due to moisture getting into the structure area. High profile structures (with straighter walls) usually work better with roll up sidewalls. When preventing a floor draft is an issue, the roll up mechanism can be raised and then the structure is lined with a skirt for the bottom 2’-3’. When using this method of ventilation, it should always be done on both sides. An effective use of this method includes opening the “downwind side totally and the opposite side on marginally.

Download our Roll up Side Wall Installation information sheet for more information

27'wide with Roll Ups roll up sides

Covering Options

Tarp Covering Instructions and Plastic Covering Instructions from the Assembly Guide can be downloaded at the underlined links

We offer 4 different types of standard coverings for your shelter solutions. We offer two types of 6 mil plastic and two types of 12 mil tarps. All of the covers can be fastened to our structures using wirelock, which is a flexible steel wire, bent into an aluminum channel on either end of the structure. This sheet is a brief overview of the options, and reasoning behind which we recommend for what application. We would be happy to answer any remaining questions you have.

The main difference between plastic and tarp beside the cost is the tear resistance. The 12 mil tarps are much more tear resistant than the plastic. The other key differences are price and life expectancy.

Plastic is the less expensive option of the covers that we offer, and is 6 mil and available in white or clear. It generally runs between 13¢-17¢/sqft depending on the size piece you require. Life expectancy is 6-7 years for single layer plastic or 6-8 years for double plastic. Clear plastic is also available in 4 mil for some cost saving but that would only be used as an inside layer. 6 mil plastic is also available with an anti-condensate and infrared coating for even greater drip control and heat savings (see below for more info on these). This plastic comes with a 4 year warranty against deterioration by the sun.

Plants need clear plastic to grow and flourish. Clear plastic is also used for swimming pool covers, as both applications require sunshine to come through. The white plastic is best when more shade is required and is ideal for livestock. It is slightly cooler inside the structure than the clear option. White plastic is also recommended for swimming pool applications where more privacy is required, as well as covering RVs or other equipment where fading would be an issue.

For greenhouses, swimming pools or livestock, we usually recommend a double cover, with roll up sides and an inflator fan. Double covers extend the life expectancy of the cover, reduce heat loss by 30%, which helps maintain the temperature in the structure, as well as reduce condensation. The small inflator fan that we offer and include in the double cover package prices, uses very little electricity and is left running all the time to keep air between the two layers so you can reap the benefits of the double cover.

Plastic can also come with an anti condensate coating which will reduce or eliminate dripping in your greenhouse. This is a detergent additive which will eventually work itself out of the plastic. This happens more quickly if you have very high humidity levels in your greenhouse. The cost is roughly 10% more then regular 6 mil plastic and is only available in full rolls (100′ or more).

One other variation on greenhouse plastic is that with an IR (infra-red) coating. The cell structure that this plastic is made from is significantly different from the regular plastic. This gives the plastic a much softer texture and feel and contributes to it not being as strong as regular plastic. This is why we suggest that it only be used as the inside layer of a double plastic installation. The slight restriction for people with shorter greenhouses is that the IR plastic only comes in 100′ and 150′ rolls. You would either have a friend who can buy/use the extra or be prepared to “waste” some. There are also not quite as many choices for available widths as with regular plastic.

The IR plastic can reduce your heat loss by up to 20% over a regular double poly installation. Even though this plastic has a hazy look to it, the light transmission properties are actually a couple percentage points better. This plastic comes standard with an anti-condensate coating which means there will be less dripping in the greenhouse. All of these features make IR plastic an attractive alternative for many people in spite of the fact that the cost is roughly  20% more then regular plastic. This plastic does not have an inside or outside.
Please call Norm to specifically inquire about more information regarding these special coatings.

Tarp is more expensive than the plastic options, but is also more durable if equipment, car doors or hay might bump against the cover frequently. It is a 12 mil three ply woven material, available in white or green. It generally runs between 38¢-45¢/sqft depending on the size piece you require. Life expectancy is 5-6 years for the green tarp and 8-10 years for the white tarp.  Green tarp comes with a 4 year warranty and white tarp a 6 year warranty against deterioration by the sun.

The green tarp consists of a green, black and white layer, which absorbs heat significantly more than our white option, which consists of a white, clear and white layer. The heat absorption contributes to faster deterioration of the green cover as well as having a higher inside temperature. The white tarp is less noticeable in the summer than the green is in the winter, if camouflaging is a concern. The white tarp also lets light in, making it easier to work inside the structure because it’s not as dark inside. Tarps are fully waterproof.

Our white plastic is available in widths of 24′, 32′, 40′ and 48′. Our clear plastic is available in widths of 25′, 28′, 32′, 36′, 40′, and 48′. Our white tarp is available in widths of 25′, 32′, and 36′ and the green tarp is available in 32′ wide. A full roll of plastic is considered as 100 or more feet and is sold in multiples of 5′ for length.

One of the less often used roof coverings is the twin wall polycarbonate. It is generally considered to be a 15 year material and it has extremely high impact resistance. The double wall with honey comb shaped flutes also gives it very good heat retention properties for a light transmitting material. It is considered as a rigid material but it does have enough flex to be installed on our gothic shaped structures. This material sells for $2.50 – $3.00 per square foot and the structure also requires some modification. This material can also be used as an end and/or door covering when durability and appearance are extra considerations.

Whichever covering option you choose, it’s important you receive all the benefits you require for your application. We are able to assist you in weighing the options further, as well as providing you a sample of each for your review. We look forward to helping you find the cover solution that best fits your needs.

Infrared Plastic Coating

Another variation on greenhouse plastic is with an IR (infra-red) coating.

  • The IR plastic can reduce your heat loss by up to 20% over a regular double poly installation.
  • Even though this plastic has a hazy look to it, the light transmission properties are actually a couple percentage points better.
  • This plastic comes standard with an anti-condensate coating which means there will be less dripping in the greenhouse.

All of these features make IR plastic an attractive alternative for many people in spite of the fact that the cost is roughly  20% more then regular plastic. This plastic does not have an inside or outside.

The cell structure that the Infrared plastic is made from is significantly different from the regular plastic. This gives the plastic a much softer texture and feel and contributes to it not being as strong as regular plastic. This is why we suggest that it only be used as the inside layer of a double plastic installation.

The slight restriction for people with shorter greenhouses is that the IR plastic only comes in 100′ and 150′ rolls. You would either have a friend who can buy/use the extra or be prepared to “waste” some. There are also not quite as many choices for available widths as with regular plastic.

Please call Norm to specifically inquire about more information regarding these special coatings.

you can see more information on our covering options page

Covering Ends – Plastic & Tarp

Please refer to the Ends page in the assembly guide as well

When you are covering the ends of the structure, there are some similarities and some fundamental differences when you are covering with plastic or with tarp.

The aluminum wirelock channel must be installed on the top side of the hoop before you start the cover. The framing must also be in place before you are putting on the cover.

Your cover will be a rectangle and you must double check if the two ends were supplied as one piece or not.

  • You start at the base of one side and go continuously over the peak so that there is not an edge at the peak.
  • The cover gets fastened, temporarily, at the base first on either side of the door and then pull out to the corners.

If there is ANY wind, do into the wind side first.

  • Please remember that whenever you have wrinkles or folds, you will pull 90 degrees to the wrinkle.

Excess on the end covers will only get trimmed off after the roof cover is on as well.

If you are covering the end with plastic

  • you would go with the extra of your rectangle and fasten it temporarily to the back side of your framing.
  • At the very most, at this stage you will put part of a wire insert on either side of the peak.
  • When the cover is sitting smooth, you can put some strapping on the vertical framing to hole the cover in place.

If you are covering the ends with tarp

  • you will need to remove the wirelock channel first.

This may seem like double work, but the channel is now curved to the building with the required screw holes.

  • The end tarp cover is sandwiched between the hoop and the bottom of the wirelock channel.
  • When you pull the tarp over the peak, you will reinstall the wirelock channel from the top and work down.
  • If you do the left, right or bottom first will be determined by where the wrinkles are (if any).

Please don’t hesitate to call if you have any questions at all and please watch the videos on our YouTube channel for more information

Choosing a Cover – Poly vs Tarp

Everyone wants to save money but they also want value for the dollars invested. One of the things that sets MSS apart is with the cover choices we offer.

The two main areas of covers we offer are the 12mil woven tarps and the 6mil plastic. (Other options available, call to confirm)

Both of these choices are by no means the heaviest that are out there, but they do provide excellent life span for the investment.

When you consider the cost per year on our 12mil white tarps, which have an 8-10 year expected lifespan, they stack up very favourably to the 20-24mil covers that are available.

  • The main reason 12mil is even an option for us to use is that our hoops or ribs are much closer together and therefore provide much more support to the cover.

Using 6mil plastic gives even more options.

  • Going clear (greenhouse) allows the necessary light transmission for plant growth.
  • Going white (livestock) allows light while still providing a shade factor.
  • The option of a double layer with air between, provides even more benefits for heat loss and condensation reduction and added stiffness in extremely windy locations.
  • The biggest attraction for the 6mil plastic is the life span you get for the investment.

Call to get your custom quote today. We would be happy to help you.
You can also see our covering page for even more detailed information

Solar Powered Inflator Fan Update & Alternative

We have been continuing to get many inquiries about solar powering the inflator fan for greenhouses and livestock buildings, which is used to put air between two layers of plastic roof cover. For the last year we have been experimenting with a solar collecting package to determine what is required, while we work to keep our interested customers updated along the way.

The first thing that must be emphasized, is that you MUST use a squirrel cage type of fan and not a propeller type. The propeller type can not continuously run against back pressure.

The output required will be determined by the size of the greenhouse or livestock building. Our regular 110 volt fan draws .25 amp and puts out 80 cfm. Some small buildings can use a smaller fan and some of the bigger ones require our double output fan which gives 130 cfm.

Our inflator fan works quite well going through an invertor. Any 12 or 24 volt fans which we have tried have been extremely noisy and therefore not feasible.

The biggest challenge which we encountered, is that the specific time the fan is needed the most for heat insulation, is also the time where there is the least capacity for generating power.

We used a single solar collector and a single battery and there was simply not a quick enough capacity for the battery to hold charge when we had several consecutive cloudy days in December/January

To add another solar collector to an already fairly expensive package, really becomes prohibitive and can deter from moving forward with it.

Based on this experience, we wanted to offer an alternative that balanced economy with feasibility. We have come up with a way where the extra roof plastic can be used on the inside of the structure.

This means that you would not need the inflator fan but still have the effect of double plastic with the air pocket for better heat efficiency. This system does require a bit of extra “fiddling” but the net cost will be a little less.

1. The structure is covered with a single layer of plastic just the same as you would if you were only doing a single layer.
2. Take the second piece of plastic inside the greenhouse and fold it double lengthwise.
3. This double plastic will be attached to the underside of the ridge using the same aluminum as you would use to fasten the plastic to the roll up pipe.
4. Next remove the purlins from the one side of the structure and after you have pushed over the plastic, reinstall the purlins under the plastic. You will be pushing the bolts through the plastic.
5. The plastic will be fastened with wirelock to the underside of the end hoops.

We have already had some customers try this out and are very happy with the result. Please call us with any questions or to discuss your specific application and situation where you might use this. We would be happy to help you with your project!

EBOOK now available!

Now available as an ebook!
So you want to buy a greenhouse… Your guide to planning your greenhouse purchase!

Check it out 🙂 and, there’s special savings if you’ve already purchased the paperback through Amazon.

If you’ve purchased the paperback at a trade show or from the office and want an ecopy, email us at multisheltersales@gmail.com with a pic of you and the book, and we’ll help you out.

https://amzn.to/2Xj5GY4

Greenhouses 101 & 202

Norm spoke at the Guelph Organic Conference January 31, 2015 on Greenhouses 101: Knowing the basics before you buy-Choices and Consquences
You can find the articles and information posted, as well as a video of his presentation and the Q&A below.

Greenhouses 101: What are you trying to accomplish? What are you dealing with?Greenhouses 101: Climate and Air Effects on your Structure
Greenhosues: 101: Covering Options
Greenhouses 101: Greenhouse Shapes & Configurations
Greenhouses 101: Orientation and Location
Greenhouses 101: Knowing the basics before you buy
Greenhouses 101: Greenhouse Choices

Norm did a presentation at the Guelph Organic Conference on Greenhouses 202: Making sure your structure survives the elements. The presentation is broken into three parts for easy viewing, the last section of which is the Q&A. These tips apply for greenhouses, storage buildings, livestock shelters, really anything we sell. Key Points Covered in the presentation:

1. Some basic principles of engineering so that the forces exerted on the buildings could be better understood.
2. The many components of anchoring. Anchoring prevents a structure from settling under snow load, prevents lifting under aerodynamic forces and prevents shifting with wind forces.
3. The similarities of an airplane wing to the shape of a structure. What happens when surfaces become bigger, wider. lower and higher.
4. How uneven loads can happen and how to prevent them.
5. The proper procedure to removing excessive snow load

Read more here: Greenhouses 202: How to get your structure to survive the elements

Watch more here:

https://youtu.be/TS1y_UmMJ38

https://youtu.be/zTAeGxObtGs

https://youtu.be/y8NGn4jqA4c

Retightening a Loose Cover

Previously we outlined how to do a temporary fix for loose cover. This should not be left for an extended period. Re-tightening a cover does not have to be done in one day.

  • The job MUST split into two parts lengthwise.
  • The cover must be pulled lengthwise BEFORE it is pulled from side to side.
  • Make sure you do the tightening process on a calm, warm day.
  • You should do the end which looks the worst first.
  • This job will require taking ALL of the cover fasteners out.

Taking a short cut will leave you with more wrinkles.
Areas with wrinkles will flutter more and cause stress points.
This will also cause the cover to deteriorate quicker.

When you are tightening the cover, you should always pull 90 degrees to the wrinkle.

This means that after you have secured at the peak,
most often you will be pulling diagonally to the corner.

Once you have done one end/half and the wind is still down, you can start loosing the fasteners on the other end and repeat the process until complete.

Please don’t hesitate to contact us if you have any questions.

You can also see additional information in our installation guide:
Tarp Covering Instructions
Plastic Covering Instructions
Wirelock & Side Wall Cover Fasteners
covering options