What is a damp proof course and why do I need one?

A damp proof course or dpc is an essential part of the construction process in that its function is to prevent rising dampness.

Rising dampness is a result of dampness in the ground being drawn up through the capillary channels in any given building fabric.

Generally a dpc will be installed when the building is constructed. In new buildings the damp proof course is physical membrane. This will be laid into a mortar course at the base of the walls. In older buildings it is common for slate or bitumen to be used as the damp proof course and some older buildings will not have a damp proof course at all.

As said, all of the above provide a physical barrier against rising dampness but why is this necessary? In short it prevents spoiling of the internal wall finishes. When a wall suffers from rising dampness the associated affects to the internal finishes is staining, salting and peeling paint or paper, blown plaster, rotten skirting boards etc.

A damp proof course is designed to stop the dampness at low level before it has a chance to do any damage higher up the wall.

Sometimes an older dpc will fail. If it does or if there isn't one can be installed as a remedial or retrofit measure. Typically one of the following methods would be used:

• Chemical damp proof course

This involves drilling a series of holes 150mm above the external ground level along the base of the walls and injecting a silicone fluid or cream. The idea is that the silicone content in these products is designed to repel moisture rising up the wall.

My opinion is that this method is a little hit and miss in that the density and quality of the wall will have a big baring on whether it will be affective as will the application method in terms of drilling hole to the correct diameter and depth and volume of chemical installed which is often very hard to gauge. This is why you will often fins a chemical damp proof course is recommended along with the removal of internal plaster and re-plastering with a waterproofing additive. The idea is if one doesn't work hopefully the other will.

• Physical Damp proof course installation

Believe it or not is possible to retro fit a physical damp proof course. Mortar joints along the walls are cut out with an electric joint saw and a new physical damp proof course is inserted in sections. The wall is then made good around it.

My opinion is that long term effectiveness should be very good however it is likely to be expensive and externally disruptive because someone is literally cutting through the walls of your house. Imagine the dust!!

• Electro osmosis damp proof course

A titanium wire is passed around the walls to be treated and at regular intervals this wire is pushed into holes made in the brickwork, then it is earthed and a safe voltage is applied, this stops the dampness from rising up the masonry.

A pretty unusual method which has opinions divided as to its effectiveness. In my opinion has never really been proved to be an effective damp proof course and as such is very rarely seen or used these days.

• Cavity membranes

Not a damp proof course as such but more an alternative to one. These systems are becoming ever more popular as an effective solution to rising dampness in buildings.

Cavity membranes are high density polypropylene and polyethylene plastic membranes. The rolls of plastic are moulded into a stud formation to give and "egg box" type appearance and for damp proofing purposes they usually have a mesh welded to the surface to provide a base to plaster or dab fix plasterboard onto.

They are described as cavity membranes because the stud profile creates an air gap between the membrane and the wall to which it is applied. Once applied to the wall (usually up to at least 1m) The membrane allows any moisture in the wall to evaporate into the air gap but because it is free to move unhindered it is not pushed to adjacent areas or higher up the wall and the membrane unlike any damp proof course will provide an impermeable separation barrier between the damp wall and the new wall finished which is permanently affective against damp, salts, staining etc. The membranes are attached using special sealed mushroom fixings and despite some concerns the membranes can be easily fixed through retrospectively if required. Plastered finish and dab fixed plasterboard and skim provide the rooms usual aesthetic appearance with the peace of mind that the membrane will prolong their longevity. In my opinion this is a good and cost effective method of treatment which can be used in conjunction with or instead of any of the above.

Read an interesting article about Damp

Damp Proofing

Damp proofing is a term used in construction and refers to a process designed to make foundation walls waterproof and prevent damp and moisture passing through walls, to indoor spaces. Symptoms of damp vary, but will generally be visible by a cold, darkened area on a wall, which may be slightly wet to the touch. There may also be a musty smell and nearby carpets or furnishings may begin to stain as a result.

Without treatment, damp can spread and eventually lead to foundation walls and surrounding decor decaying. It can be started with something as simple as a nail destroying the integrity of an exterior brick and allowing moisture to slowly pass through from outdoors. It can also be caused by poorly installed former damp proof courses (or their entire absence, in older buildings) and damage done through bridging - where floor or ground levels are changed. Damp can build up over periods of years, which is why some causes may not become visible for some time. It can also be more of a problem with stone, brick and mortar - which are porous materials and will allow damp to rise upwards, carrying ground salts which can add to the dampness problem and break down plaster and decor over time.

Caught early however, damp proofing can be applied with excellent results. A damp proofing course will involve a barrier being installed into a wall that resists the rising moisture using a capillary action - preventing what's known as rising damp. It will also have a damp-proof membrane to prevent similar passing damp on solid floors- known as DPM or DPC.

Damp-proofing is best done by an expert, as it isn't an absolute and clear cut diagnosis - a trained technician will carry out tolerance tests, diagnoses and methods tests before diagnosing and recommending a course of treatment. This may involved flexible materials such as plastic sheets or lead and copper to prevent damp, mortar being applied with waterproof properties and compounds, thick continuous spread plastic sheets being laid under floors and rigid materials such as slates or cement being painted with a special bitumen.

A very effective (and cost effective) approach to permanently avoid the problem of damp is to apply an exterior wall system, which is a special, durable exterior paint coating. Companies such as Never Paint Again offer an exterior wall system which is suitable for any type of wall surface, including

•          Stucco
•          Stone
•          Brick
•          Plaster
•          Metal and more

Master builders will treat all surfaces and repair defects before the coating is applied. Different textures are available, from smooth, fine and coarse and the benefits are significant, including:

A stop to condensation build-up in the home Reduced wind chill, leading to lower energy bills Instant prevention of inner and exterior damp on walls Removes the need to repaint walls on an annual basis Installed and applied fully by expert teams, with prior wall fixing for a prepared surface Offers flexibility and an attractive finish, with different finishes and colors on offer

Most importantly, the system works on any type of exterior wall, making it suitable for any home keen to avoid problems with damp.

Read an interesting article about Damp Proof Course

How To Recycle Xerox Printer Cartridges?

With the millions of users of Xerox printers, we can also expect millions of empty Xerox printer cartridges that are disposed worldwide. How and where will these tons of cartridges will disposed is up to the consumers. It is not uncommon to see people and business establishments throwing away empty Xerox cartridges in trash cans. It is also not uncommon to meet people who are ignorant on the proper way of disposing spent cartridges. Throwing away empty cartridges is an irresponsible act against the environment which is already damaged due to our irresponsible activities.

When thrown to the outside environment, say landfills, printer cartridges release toxic compounds that can pollute soil, water, and air. Imagine the amount of toxic substances released in the environment if million tons of Xerox print cartridges are dumped in landfills. You need to know that cartridges are not like plants and animals that can be decomposed by natural means. Majority of the parts of a cartridge are non-biodegradable or cannot be decomposed by microorganisms. In fact, there are materials in the cartridge that are made up of sturdy polymers that take hundreds or even thousands of years to disintegrate.

With the growing public demand for corporate social responsibility, many printer cartridge manufacturers like Xerox are developing recycling programs to reduce the volume of cartridges dumped in landfills or elsewhere. They also continuously improve their manufacturing process to reduce waste up to zero. Moreover, environmentally friendly materials are being used to minimize the amount of toxic substances released in the environment.

Xerox, one of the leaders and movers of the printer supply industry, has been collecting empty toner cartridges for years now. It has a worldwide program called Xerox Green World Alliance which is boasting 145 million pounds of waste out of landfills since its launch several years ago. A great bulk of these million pounds of waste is empty cartridges. Xerox collects these cartridges from customers and recycles them. They use the various parts of the recycled cartridges to make brand new ones for sale. Some of these parts can actually be recycled more than twice depending on their conditions.

Returning genuine Xerox print cartridges for recycling is easy and free. Whatever the number of cartridges you are willing to return, Xerox will gladly accept them. All you need to do is visit the official site of Xerox and look for the page about Green World Alliance Program. In this page, you can request an eco box with ready to use shipping label. Put your empty cartridges in the box, seal it properly, and hand it over to UPS which will handle the shipping of your eco box. That's it my friend, you are done.

Read an interesting article on Whiteboards

Card laminators and Card Printers

For most business owners and managers there is no mystery at all in relation to which office gadget to buy: a card printer or a card laminators. They are totally sure of their requirements and expectations; know how much money they can invest in this new technology advancement and are determined to buy what they consider will help them solve their card printing needs. In many other cases, business owners and managers are still doubtful about which device to buy and would really appreciate if somebody provided them with some kind of comparative analysis between the two of them. This article is just written for them. Go on reading and understand what the difference is between a card laminators and a card printer and what their advantages if any are.

As regards the quality of the finished ID card is concerned, there is no doubt at all that if you are really looking for highly professional and neat ID badges you should consider buying a card printer. It works with plastic or PVC cards that do not need to be laminated. On the other hand, a card laminators may leave bubbles if it is not well used and all cards will have a plastic border around them.

If you need to produce a lot of ID cards over a limited period of time, your best alternative is buying a card printer. Some of these devices can be really powerful and they can deliver over 200 identifications in only one printing session. On the other hand, if your printing needs are not so demanding you can consider purchasing a card laminators. If you opt for a cold one, you will be able to produce lots of ID badges in a quite fast manner as you will not have to leave the device to cool down.

Card printers have an additional advantage. Once the information is introduced into the card software system and all the blank cards are loaded, the printer can do everything by itself with little or no supervision at all. Card laminators require more manual effort as cards have to be introduced individually in the laminating pouch.

But if you are interested in versatility, you should definitely consider buying a card laminators. It will allow you to laminate not only identification badges but also any other document or paper you may need or want to have protected from the daily tear and wear such as a memo, a fire exit plan, a price list and so on.

Read an interesting article on coat stands

Customized self-adhesive labels

Custom self-adhesive labels can be found everywhere in our lives; they are found as price stickers, product labels, food labels, you name it. With a custom self-adhesive label, you find an indispensable commercial resource to promote and advertise your business image.

There are different types of self-adhesive labels. The difference lies in the adhesives and different backing liners that range from permanent to low tack. You choose the best type of self-adhesive label to customize it. You can raise brand awareness of your business with a customized self-adhesive label that has your logo or name on it.

The permanent sticker is the most difficult to remove; there will be some adhesive residue remaining when you try to remove this label. The removable labels are only for temporary use and can be removed easily without tearing or leaving glue or any material behind. Low-tack self-adhesive labels adhere to a flat surface with static cling.

When choosing the custom self-adhesive label for your business, you have to take the environment into consideration. The paper labels are not advised for outdoor use as they deteriorate with moisture and UV light exposure. The custom self-adhesive label comes in an infinite choice of colors and materials in either matt or gloss paper finish.

Labels are usually ordered from a color printing shop; however, the custom self-adhesive label has to be ordered from screen printers or from specialist digital label printers. This is because you can supply your own artwork or your brand image here to make your custom self-adhesive label. When creating your custom self-adhesive label, it is important that you mention to the printer where you intend to use the label. Mention whether it is to be used in interior or exterior conditions, permanent or temporary or inside or outside of glass.

Read an interesting article about office supplies

Deck Sealer

When choosing and applying a deck sealer, consider the following:

1. You have choice. You can select just about anything when it comes to deck sealer, you can select a penetrating clear or tinted sealer or a solid color stain. This is totally up to you, and it is pretty much a preference matter.

2. Buy a clear or semi-transparent stain if you want the grain of the wood to show through. This is a beautiful option if you have a deck made from a beautiful wood. If however you use a composite wood, or the graining pattern is bad, or warped, then a clear or semi-transparent stain is not a good idea.

3. You should buy a solid stain if you want the finish to look like paint. Just don't use paint as often this is not enough to protect your deck from the elements.

4. Consider water. Latex or not, you want to make sure the stain or sealer you chose for your deck is labeled "Water Repellent", this is important because you do not want your wood deck to absorb water.

5. Know what the product is good for and not good for, for example, do not use clear finishes such as polyurethane or varnishes as they will degrade under the sun's UV rays, and require more maintenance.

6. Be sure to apply your stain or sealer generously, remember wood absorbs, and often is very porous, so assume nothing. When using a roller for the large flat deck board areas, roll on the sealer or stain, and spread it quickly as it absorbs quickly and you want full and even coverage.

7. Deck dealer should not just be applied to the deck floor, there are other parts of the deck as well such as the railing and balusters. It does not matter how nice the deck floor looks if the railings look worn, older, and weathered. So, for railings, balusters and in between deck boards a roller won't work so use a brush and be thorough. You do not want your deck to look aged simply because you were lazy and missed some spots.

8. Deck sealer dries quickly and you can use your deck again within a few hours, but for best results really give it time to dry thoroughly. Also, do not apply it if there has been rain in the past couple of days, you want to be sure the deck is thoroughly dry before application, so plan accordingly.

9. Sealers won't stick to grease, so pretreat any grease stains caused by drips from grill by scrubbing with a solution of soap and hot water. Even precleaning does not ensure removal of grease from grills, so be thorough here as well, or your sealer may not bond well to the wood. Clean your deck well to get the best adhesion.

10. With whatever deck sealer you choose, be sure to follow the manufacturer’s instructions, it is their product and they know best, so for best results follow directions.
 
Your deck will look better and last longer if you follow these ten easy suggestions to get the best product and best application possible.

Read an interesting article on Patio sealer

Tanking slurry To Avoid the Problem of Ground Salts

Cellar Tanking is a term used to describe the waterproofing of a cellar, it is often applied as part of a cellar conversion project or may be installed on its own to create a dry storage space.

By definition, cellar tanking systems are bonded to the walls and floor of an otherwise wet cellar, with the aim of holding back water or dampness, to produce a 'waterproof tank'.

Ground water contains dissolved salts, particularly Nitrates, Chlorides and sometimes Sulphates. They can affect cement based tanking systems in two different ways:

• Sulphate Attack of Cement 
• Growth of Salt Crystals (Chlorides and Nitrates)

1. Sulphate Attack

This is a reaction between the Sulphate and the Calcium Hydroxide and Calcium Silicate hydrate in the cement paste, it results in cracking, expansion and loss of bond between the cement paste and the aggregate with ultimate failure of the tanking system. 

Sources of Sulphate include:

•  Seawater (so be wary in coastal areas) 
•   Oxidation of Sulphide in adjacent clay 
•   Bacterial action producing Sulphur dioxide, which dissolves in water and then oxidises to produce Sulphuric acid.

2. Growth of Salt Crystals.

These can grow within or behind the render of the tanking system itself causing the render to crumble or delaminate. Why do salt crystals grow and what do they look like? The answer to this is simply that ground water contains dissolved salts and as the water evaporates the salt gets left behind, just like it does on a kettle element. So any 'breathable' render will allow salt crystals to be deposited at the point of evaporation, which may be within or behind the render. They are normally white in color but sometimes have a yellowy tint. If water is evaporating from the surface of the wall they will appear as wispy filaments that often get mistaken for mold.

In order to avoid the risk Sulfate attack the ground water should be tested for Sulfates, and if found to be present, a tanking system should be selected which is non-cement based. If cement based tanking material must be used, for whatever reason, then a salt inhibitor based on Zinc hexafluorosilicate (also known as Zinc hexafluoride - ZnSiF6) can be used, it is available under various brand names and is easily obtained from most specialist material suppliers. This should be applied to the masonry before the cellar Tanking slurry or render. Particular attention should be paid to the health and safety data which will normally be supplied with the the product.

In order to avoid damage by the growth of salt crystals a tanking system can be selected, which is non-breathable, a bonded sheet membrane would fit this category but be aware of limited ability to hold back water pressure. A non-bonded plastic or foil lined cavity drainage membrane is the best, as these allow water pressure to dissipate - see my other article on 'cavity drainage membranes'.

Read an interesting article about Liquid DPM