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Guaranteed 25 years
Collstrop and the environnement

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Guaranteed 25 years

25 years guarantee  
"Durability" and "outstanding quality" are not just idle words that we use.  Whatever we say, we guarantee in writing : a guarantee of at least 25 years against fungus degragation or the attack of insects !  We can only make this possible by selecting the finest timber, and by carefully following the correct pressure impregnation procedures.
1. What kind of wood to choose ?
When buying garden wood, the first decision you have to make is whether you want impregnated redwood or tropical hardwood?
Tropical hardwood has the property to become silver grey and has a natural outstanding durability.  Remember that not all hardwoods have the same durability.  So make sure that you buy the correct hardwood for your application.  Excellent timbers are Bilinga, Padouk, Ipé and Itauba.
Impregnating softwood is more than just colouring the wood green.  A professional pessure impregnation can only be carried out when using the best timbers and the correct impregnation technology. 
2 . The impregnation
Just plunging the wood into a green bath, as some companies do, does not protect the wood against long term degrading.  Only an impregnation in a vaccum tank offers you the correct results.  Not all kinds of timber can be impregnated to the same quality standards.  Whitewood (Spruce) will only allow fluid penetration right through the sapwood to the heart and even partially into the heartwood. 
The stamp
All of our ready made Collstrop products have a special branded guarantee stamp.  The presence of this stamp should always be checked, as it is your guarantee of a good investment and not an imitation.
Garden Wood
As the Garden Wood is usually cut ans shaped after purchase, it is impossibe to place on every piece the guarantee branding mark.  For this reason we cannot give a written guarantee of 25 years, but despite this we know that Garden Wood products are just as durable when the cut part is treated again with Collstrop Special Treatment.  We would be happy to discuss potential concerns.
A lot of products in our catalogue have the LSQ-label.  LSQ stands for Long Standing Quality and is a quality label for Northern redwood which has been treated with a special water repellent additive that protects the wood against water damage.  During the pressure impregnating process, a type of liquid wax is pressed into the wood, which effectively closes the cell openings.  By restricting the variation in change bewteen wet and dry conditions the possibility of shakes, twists and ageing is greatly reduced.
One post = one tree
Wood is a natural material and shakes or splits will occur.  They have no effect on the quality, structural properties or durability of the timber.  Posts are especially prone to show cracks in summertime because they dry out and the heratwood is in the middle of the post.  The tension of the sapwood and the heartwood is different and this creates shakes in long periods of dry weather.  After a rainy period these cracks will disappear as the timber absorbs water and swells.
Suplliers of cheaper post saw 4 posts out of one centre of a tree.  The cracks have less chance of occuring but by exposing the heartwood, the post is certain to deteriorate quicker.  The heartwood is exposed and cannot be treated.  The chance of deterioration is therefore higher.  Moreover these posts have a greater chance to wrap due to irregular tension in the post.
Did you know that all the timber used at Collstrop comes from durable and sustainably managed forests, where more trees are planted than cut. We work hard for the conservation of the forests throughout the world.  By using pressure impregnated wood the life span is prolonged and it enables less timber to be cut down for replacement purposes.
The Cras-group, the producer of the Collstrop articles, is a member of FSC, Forest Stewardship Council and has his own FSC-Label. Products carrying the FSC label are independently certified to assure consumers that they come from forests that are managed to meet the social, economic and ecological needs of present and future generations.
Is impregnation harmful for the environment ?
Some impregnation products can be harmful to the environment when used is an unprofessional way.  Cheap products and poor controls allow the product to leach out after some time.  When using the exact concentrations, and when following the correct impregnation procedure, there is no harm to the environment.  It is very important to buy timber from reliable suppliers, such as Collstrop, who have an industry brandname.  This is also your way of saying 'I will only buy from respected companies who are regularly submitted to examinations by independent authorities'.