Is there a better sealant than silicone?

Spaces between bricks filled with mortar

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In masonry, mortar joints are the spaces between bricks, concrete blocks, or glass blocks, that are filled with mortar or grout. If the surface of the masonry remains unplastered, the joints contribute significantly to the appearance of the masonry.[1] Mortar joints can be made in a series of different fashions, but the most common ones are raked, grapevine, extruded, concave, V, struck, flush, weathered and beaded.

In order to produce a mortar joint, the mason must use one of several types of jointers (slickers), rakes, or beaders. These tools are run through the grout in between the building material before the grout is solid and create the desired outcome the mason seeks.

Repointing

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Although good-quality bricks may outlast civilizations, the mortar that bonds them can crack and crumble after a number of years. Water penetration is the greatest degrader of mortar, and different mortar joints allow for varying degrees of water-resistance. For maintenance, degraded mortar joints need to be renewed by removing the old mortar and applying new mortar, a process known as "repointing".

Types of joints

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Mortar joints in brickwork take up a considerable large amount of a wall's surface area and have a significant influence on the wall's overall appearance. Some joint profiles accentuate their individual designs, while others merge the bricks and mortar to form a flush, homogeneous surface. Mortar joints vary not only by their appearance, but also by their water-resistance properties.

The following are the most common types of mortar joints:

Concave joint

This popular type of joint is formed in mortar through the use of a curved steel jointing tool. It is very effective at resisting rain penetration due to its recessed profile and the tight seal formed by compacted mortar. Patterns are emphasized on a dense, smooth surface, and small irregularities are hidden.

V-joint

This type of joint can be made with a V-shaped jointer or a trowel soon after the bricks are laid. Ornamental and highly visible, the joint conceals small irregularities and is highly attractive. Like the concave joint, the V-joint is water-resistant because its formation compacts the mortar and its shape directs water away from the seal.

Weather joint

Mortar is recessed increasingly from the bottom to the top of the joint, with the top end not receding more than 3/8-inch into the wall. The straight, inclined surfaces of the bed (horizontal) joints tend to catch the light and give the brickwork a neat, ordered appearance. This joint is less compacted than the concave and V-joints, although it is still suitable for exterior building walls.

Grapevine joint

While most popular during America&#;s Colonial period, this design is often replicated in newer brickwork. It is created with a grapevine jointer, which is a metal blade with a raised bead that creates an indented line in the center of the mortar joint. These lines are often rough and wavy, simulating the generally straight yet slightly irregular appearance of a grapevine. It is commonly used on matte-finish and antique-finish brickwork.

Extruded (squeezed) joint

This joint design requires no tooling and is formed naturally as excess mortar is squeezed out from between the bricks. The result is a rustic, textured appearance. This design is not recommended for exterior building walls due to the tendency for exposed mortar to break away, degrading the wall&#;s appearance.

Beaded joint

Raising a rounded, bead-shaped segment of the mortar away from the mortar surface produces this old-fashioned, formal design. Although beaded joints can create interesting shadows, they are not recommended for exterior use due to their exposed ledges.

Struck joint

This joint is formed in a similar fashion as the weathered joint, except that the bottom edge, instead of the top edge, is recessed. It is not water and weather resistant, as it will allow water to collect on its bottom ledge.

Raked joint

For this design, mortar is raked out to a consistent depth. Although often left roughened, it can be compacted for better water-resistance. This design highly emphasizes the joint and is sometimes used in modern buildings in order to match the historic appearance of their locales. Unless it is compressed, it is not as water-resistant as other mortar joints because the design incorporates ledges, which will collect water as it runs down the wall. Also, when mortar is removed from the joints, it becomes smeared on the surfaces of the brick at the recesses. To remove the mortar, contractors often aggressively clean the walls with pressurized water or acid solutions, which can open up additional voids and increase the possibility of water penetration.

Flush joint

This joint is best used when the wall is intended to be plastered or joints are to be hidden under paint. Because the mortar is not compressed, it is less water-resistant than some of the other designs.

Tuckpointing

This joint has mortar colored to match the bricks surrounding a line of white mortar to make the joints look very small. The white portion of the tuckpointed joint stands proud of the bricks.

References

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• Mortar joints at bontool.com: diagrams of the various kinds of joints

Polyurethane Sealant VS Silicone Sealant - Difference Between Silicone and Polyurethene Sealant

A sealant is a versatile material, whether it's silicone sealant or polyurethane sealant.

Either way it forms an integral part of most people's toolkit - DIY or Professional.

If you're interested in doing jobs around the house or you're part-way through a Professional renovation project such as bridge building or even Coach Building panels.

Whether you're planning to modernise a property or revamp the bathroom, here's one thing we know.

It's highly likely that in selecting the best sealant for the job, you're given it some serious thought.

Which is no easy job.

There are various forms of sealant or mastic sealant available, so which is the best option for you.

Here's why it is so important to spend time weighing up the options.

Hopefully, this guide will provide the regarding the difference between silicone and polyurethane sealant.

A brief introduction to mastic sealants

A sealant is a form of material, which is used to seal gaps and holes to make something airtight or watertight.

When you use sealant, you effectively form a seal, which prevents the movement of fluids and liquids.

Sealant is sometimes compared to caulking.

The main difference between building caulking and sealing is the flexibility of the seal. If you include mastic sealing in this equation sealants can not only seal but can also be used as an effective adhesive.

Sealants tend to be made from much more flexible materials.

This makes them useful for areas and joints where a degree of contraction or expansion may occur.

Polyurethene Sealant Properties

Mastic sealants such as polyurethane tends to be especially used in professional industries such as bridge building or automotive coach building. It's hard wearing approach and exceptional adhesive properties means it works well for professional applications where strength and speed are crucial.

Polyurethene sealant can also be used effectively in joinery because the sealant cures quickly and exceptionally hard into wood joints. These joints can then be sanded and painted over for a top quality finish.

They are not the same as adhesives, but it is possible to utilise sealants that have adhesive properties.

Sealants are used widely, and may come in handy for those working in the following industries:

• construction
• automotive
• engineering
• aerospace
• marine
• joinery
• road building
• bridge building

As well as those with an interest in DIY and property maintenance. There are many different forms of sealant both silicone and polyurethane sealants. This guide will focus on silicone and polyurethane sealant although these sealants have similarities, there are some significant chemical differences.

Are you interested in learning more about OSi Silicone? Contact us today to secure an expert consultation!

One of the principal differences between silicone and polyurethane sealants is the chemical composition. Silicone is an inorganic substance, while polyurethane is organic.

The primary difference between organic and inorganic substances is the presence of carbon. Organic compounds contain a carbon atom. In most cases, a hydrogen atom is also present. With an inorganic substance, it's uncommon for either atom to be present.

Polyurethane is a polymer, which comprises of a series of organic atoms connected by carbamate. Silicone is a unique material because it contains both inorganic and organic compounds.

These synthetic polymers comprise silicon and oxygen atoms, which are joined using C-Si bonds. The makeup of the chain exposes the organic elements of the structure to external influences.

This is why silicone makes such a versatile sealant for DIY as it can do most jobs satisfactorily - it's non organic composition makes it fairly dependable across the board and long lasting. Silicone is commonly used in construction and the development of paint and food products.

Chemical Breakdown

The chemical makeup of both silicone and polyurethane sealant are important. This is because the composition affects the breakdown of the materials. When organic and inorganic substances are exposed to UV light from the sun, the way they react differs.

Inorganic materials are less responsive to UV rays than organic chemicals. In the long-term, polyurethane, an organic material, will revert back to its natural state in response to UV exposure.This affects both the lifespan and versatility of polyurethane sealant. Polyurethane sealants set exceptionally fast and exceptionally hard as the organic compounds react faster with UV light.

This makes them especially useful for professionals working outside in industries such as road and bridge building. Polyurethane still has sealant and adhesive properties that exceed silicone and the fast acting nature helps project planning.

Paint and Sealants

(image courtesy of House Painting Tips with Silicone)

A key player in the discussion between silicone sealant and polyurethane sealant is paint...If you use paint (spraying, roller or brush) and need an adhesive or sealant in close proximity to your finished paint work. You will have come up against the common issue of silicone!

Silicone cannot be painted over its inorganic compounds will not allow paint to adhere or absorb into its top layer surface. The paint will simply peel off or in most cases simply run off during painting.

Polyurethane sealant is organic and after curing time it can be painted over and even sanded successfully to the same finish as other surfaces. This provides a huge advantage over silicone for both the DIY'er and professional alike.

Time Debate - Will my Mastic Gun be out sooner with Polyurethane?

It could be argued that silicone lasts longer (being non organic) than polyurethane (organic). Typically, a polyurethane sealant will produce effects that last between 5 and 10 years. While a silicone joint could last more than 20 years.

Most professionals however would argue that the quality and harder nature of Polyurethane sealants slightly edge out the longer lasting nature of Silicone. It's potentially why silicone is used more frequently in the home - where traffic and use is reduced. While polyurethane sealants are more prevalent in professional situations where drying time and hardening qualities are more crucial.

Which Polyurethane Sealant?

We always advise the Soudaflex 40FC range which is a high quality polyurethane sealant and adhesive perfect for a wide number of applications.

By far the biggest market for Soudaflex 40FC is the Coach Building Industry. It is perfect for bonding and sealing panels. It is also a high quality joint sealant, being used in road and bridge building, as well as industrial flooring applications.

Sold by the by the box (12) we have large stocks of all colours.

Colours White, Black and Grey Tube size is 310ml

Advantages & Benefits of Soudaflex 40FC Adhesive and Sealant:

• Very good adhesion on many materials
• Stays Elastic after curing
• Over Paintable**
• Very easy application
• Excellent resistance to many chemicals
• Developed for concrete applications
• Structural bonding in vibrating constructions

** Whilst Soudaflex 40FC is over paintable, a test area is recommended. Also 40FC is a flexible sealant and adhesive where the paint generally will not be. Cracks may appear in time as the sealant moves and the paint does not.

Buy Ultrimax supplies the full polyurethane sealant and mastic gun

310ml Black, Grey or White

Need More Help Selecting The Correct Silicone Or Polyurethane?

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