How do you go about fiber cement board installation details ? If you are a cladding contractor bidding a decent sized job you will need to submit cladding drawings to the Architect or builder to demonstrate you understand what's involved in the job and have looked atout all the potential difficulties with the installation
What is fiber cement cladding ? It's a hard panel usually ½ inch or 13 mm thick made of fiberglas fiber reinforced concrete. These panels are hard wearing, long lasting and can be made in all sorts of colours and finishes.
Fiber cement cladding is a lighter, more environmentally friendly material that takes the place of a brick facade. Fiber cement panels are nowhere near as heavy as a brick facade. The amount of energy required to make and transport bricks is way higher which leads to the environmental benefits of fiber pa
The weight of panels must still be considered since it must be carried by the existing building structure typically using a system of steel subgirts and hatbars. These subgirts are tied into the buildings structure which might be existing structural steel, brick, wood or concrete.
To deal with dead load of the panels two or more fasteners in each panel are dedicated as "Fixed point dead load fasteners". These are carefully sized to ensure the weight is properly carried and are made so that there is no clearance to allow panel movement. The remaining fasteners on the panel are termed "active fasteners. These have hole clearance to allow building movement caused by wind loads and building creep as well as thermal expansion.
As well, specific subgirts can be specially designed to support the weight of extra large panels. Double fasteners may also be used at times when loads from snow and wind are particularily high. In highly insulated buildings, the thickness of the insulation can cause the subgirts to experience too much deflection requiring redesign. The spacing of subgirts is affected by the loads required and this in turn may change the location of fasteners.Fasteners
Fastening methods for FC panels include screws and rivets. Rivets are generally favoured because they are inherently tamper proof and have minimal impact on the look or aesthetic of the panel. They also allow more consistency during installation. Rivets used will typically be aluminum or stainless steel. A key requirement is the surface coating for the head of the rivet. Powder coated finishes matching the colour of the panel are preferred due to the ability of the powder coating to stand up to the weather.
Screws can also be used to secure panels and there are a number of tamper proof designs available. These typically involve special tools for installation and removal. Screws can also be purchased with decorative attachments to cover the heads. In this way the screw shape can be incorporated into the facades aesthetic.Soffits made of fiber cement panels
Soffits made with fiber cement cladding also require special treatment for loads in the the dead load of the panel may cause "creep " or sagging. In soffits as well as the edges of wall cladding, the cantilever of the sub girts beneath must be restricted to make sure winds to pull off the edges of the panel.
Tools for installation involve special saw blades designed specifically for cutting cement panels. For best results, panels should be precut with a precision table saw and then delivered to site. There are excellent panel cutting saws available for doing trim work on site. Another factor in cutting is dust control. Tools need dust collection apparatus and workers need facemasks to work with cement panels as the dust raised by sawing can be hazardous.
The following methods apply to fiber cement cladding but is little different regardless of the cladding material be it composite aluminum panel, steel sheathing or good old fashioned board and batten construction.
The first step in creating fiber cement board installation details involves identifying the areas where the cladding has to be installed. This process requires the creation of a “Key Plan” drawing.
On the key plan we put arrows denoting each elevation on which cladding has to be installed. The Key Plan is based on the architectural plans and structural steel drawings. When structural steel columns exist you have a good way to verify the girt line which defines the extent of the girts that are needed to support the fiber cement panel.
Start with the architectural plans which show areas requiring cladding installation. A separate keyplan will need to be completed on each elevation requiring windows or cladding. Resist asking for architectural drawings in CAD format, you must verify dimensions and geometry against existing plans. If you use CAD drawings there may be errors and omissions which you just end up copying into your own drawings.
Architectural plans are usually available in pdf format. Use these and trace or sketch your fiber cement board installation details over top, verifying dimensions as you go. I use PDF underlay in AutoCad 2011 to import the architectural plans into my own CAD drawing.
I typically insert the pdf with no regard for scale and then zoom in on one of its horizontal or vertical dimensions. I place a dimension directly over top and check if I get the same number. Usually that is not the case so I use the two dimensions to calculate a ratio to scale the pdf up or down. If the calculations are correct, the dimensions will match after the scaling process.
From then on its just a simple matter to place dimensions one after the other, checking to see if they always come out identical. Any dimensions that come out wrong after the scaling and checking will likely be drawing errors from the original drawing. Your layout must be 100% accurate.
Start by laying out the grid lines and their dimensions. If no grid lines are shown, use the ground floor plan as a basis. Concentrate on accurately transcribing the outside profile of the building paying close attention to window and door openings.
What I usually do is set the entire building profile to a layer called “Phantom” with the phantom linetype and lineweight set to fine. Any areas where my installation work is involved I represent with a single line. I switch to “Object” layer which has a continuous linetype and a heavy lineweight.
When you have finished transcribing geometry and dimensions, copy the entire drawing and delete the underlying pdf. This will reveal your drawing with dimensions, grid lines and the complete outside profile of the building. The areas involving cladding or window work will stand out as the areas drawn in the red object layer.
The reason for copying the drawing is to retain the pdf for later reference and checking
To finally create the key plan I copy the drawing once again and erase everything except the phantom layer and object layer. This leaves me with a clear accurate indication of the areas where work must be performed. To finish, I then add in markers to identify each object layer area as a separate elevation with its own drawing number.