How To Compare Quality When Assessing Quotes For An Outdoor Classroom

How To Compare Quality When Assessing Quotes For An Outdoor Classroom

We totally understand and appreciate that you have to get at least three competitive quotes for your outdoor classroom/shelter project. And sometimes this can be quite daunting because although these buildings might initially all look the same, there are perhaps certain very important differences which you need to take into consideration before making the final decision on which supplier to use.

 What Is The Roof Structure?

This is where the majority of problems occur. You need to consider therefore what materials and the quality of these materials a company is providing.

• If they are using a ship lap or timber weather board roof, what is the wood and is it treated in any way? If a cheap wood is being used (such as a white wood or untreated pine), it will eventually warp and bend leaving open cracks in the roof sections which will allow in moisture and the wet. Your outdoor classroom will therefore not be waterproof and will eventually be prone to rotting over a period of time which will eventually need replacing. This “cupping” effect could also force the timbers to come away from their supporting rafters, thereby exposing dangerous nails or screws which are a safety hazard to the children.
• Is an underdrawn roof ceiling being installed at all and if so, what is the material being used? A lot of companies use plywood but you must ensure that it is a marine or exterior grade ply. If it is not, it will simply rot over a relatively quick period of time which will also cause it to bend or sag. To give absolute longevity however, it really should be a pressure treated plywood which has a greenish hue to it and which gives it added resistance to mold and mildew.
• Do they use any kind of waterproof membrane at all on the roof?
• We use a weather resistant, water absorbing armourglass felt shingle tile or cedar shingle tile which will last for 15 years plus. Below this, we install a waterproof membrane (to stop any excess water ingress) and our internal ceiling is an attractive solid log finish which is treated to a grade 4 tanalith level to give extra protection and longevity

What About Cracks and Shakes?

A piece of wood eventually grows cracks or “shakes” regardless of how well-dried it is. This inevitable occurrence is due to seasonal changes particularly in terms of the relative air humidity and timber trying to harmonize with its surrounding environment. Moreover, there are other significant influences that cause wood shrinkage.

The issue then is not how you can avoid seasonal wood shrinkage; the real question to ask is what the best thing is that can be done in order to slow down the shrinking process. One of the most important things to consider is good quality wood treatment. A good treatment basically controls how fast moisture enters and leaves the wood.

Round poles or posts for instance are often used for outdoor classrooms. However, these type of timbers suffer from radial cracking where they split or crack along the radius. It does not lessen the strength of the timber per se but if they open up too much, inquisitive children will undoubtedly try to stick their fingers in it and get splinters. And if the timber has not been treated in any way, these cracks will allow moisture to enter into the pith (heart) of the timber which will eventually exasperate the problem even more.

What Makes A Quality Treatment?

Preservative pressure treatments will significantly extend the service life of timber by providing an effective protection against all forms of wood decay and insect attack. Carried out in industrial treatment vessels by trained operators, treatments use a proven process of pressure and vacuum cycles to impregnate the wood preservative deep and permanently into the timber cells.

The eventual end use of preservative treated timber is classified into one of five main categories. These Use Classes, defined in BS EN 335-1, are based on the potential threat to the timber from decay or insect attack in its eventual application.

You also need to ensure that if the timber support legs for an outdoor classroom are being dug into the ground, extra protection is put around each post. If this is not done, the timber leg will completely rot underground from the damp ground conditions.

We only use Class 4 timbers which affords the highest degree of protection. And we always use Post Saver sleeves for timbers which are dug into the ground and are proven to prevent ground rot. Post Saver sleeves will save you money, time and material failures in the future.

For further information on our outdoor classrooms range, please call us on 01832 275902 or email us on info@hideouthouse.com