Roof Components - Rafter Input

Using the "rafter entry" function you can enter arbitrary rafters. This can be done as individual rafters at specific positions, but you can also split fields. The program distinguishes three rafter types.

Rafter types

• Fixed rafter: The fixed rafter is entered as an individual rafter and in the input dialog box receives the setting "Yes (Fixed rafter)" in the field "consider as field boundary". This causes it to be considered a field boundary when distributing field rafters. The fixed rafter always remains at the initially chosen position. The fixed rafter is displayed in dark red in the roof structure.

• Field rafter: The field rafter is entered by splitting a field and is displayed in "normal red". This rafter remembers the splitting rule with which it was created. If a field boundary shifts later, the field rafters redistribute themselves automatically. If you move a field rafter it automatically becomes a fixed rafter and there are two possible reactions for the remaining field rafters:

  • The other dividing rafters to the right and left of it redistribute themselves automatically.

  • The two adjacent field rafters to the right and left of the moved rafter also become fixed rafters and the splitting rules of the remaining field rafters are adjusted so that they remain at their old positions.

• Additional rafter: The additional rafter is entered individually like a fixed rafter and in the input dialog box receives the setting "No (Additional rafter)" in the field "consider as field boundary". Thus it is not considered a boundary when distributing field rafters; it is ignored as if it did not exist. This allows, for example, entering blind rafters. The additional rafter is displayed in a light orange-red in the roof structure.

Rafter settings

The following settings can be made for the rafters:

Using the selection list at the top of the dialog box you can choose existing settings. With the disk icon you can save the current setting under the same name or a new name. Via the management icon you can create new settings, including by adopting existing settings, or modify or delete existing settings. See "Save settings" in the "General Help" manual.

Identification number: The identification number determines the rafter material. Using the button at the end of the field you can branch into the database and select a material.

Bar type / designation: Bar type and designation are now determined as in other component entries:

▪ There is no longer any limitation on the bar type.

▪ The standard designation is adopted according to the bar type but can be adjusted arbitrarily.

▪ If the bar type and designation are left empty, both will continue to be assigned automatically: depending on the situation of the individual component the bar type and designation for rafters, hip rafters, valley rafters etc. are entered automatically.

Thus it is possible to label rafters that are used for special components accordingly, e.g. additional battens in the verge area, insulation strips. By adjusting the bar type these components will not be regarded as rafters in certain situations:

▪ The component can be excluded as a support for the formwork. In the case of rafter-oriented this searches for at least 2 rafters as supports.

▪ The component can be excluded as a reference component for the generation of counter-battens:

Counter-battens are generated on rafters with the following bar types:

- Rafters: 110-139, cheek rafters: 170-179

- Filler wood 142: The length of the counter-batten is reduced to the length of the filler wood

- Ridge / valley rafters: 210-229, cheek rafters: 270-279

Width: Width of the rafters.

Height: Height of the rafters.

Position: Position in which the rafters are installed. The rafters are flush with the upper edge of the specified position.

Lowering from top of position: The rafters can be lowered by this value. This dimension is measured from the top edge of the position set above to the top edge of the rafters.

Positioning: With the positioning you specify which point of the rafter should be positioned:

Choice: With the "choice" option you can, after selecting the point at which the rafter is to be placed, graphically select the different positioning options. The program starts with one position; you can choose the next option with the right mouse button and accept the current position with the left mouse button.

Left edge: The left edge of the rafter, viewed from the eaves of the selected roof surface, is positioned.

Axis: The axis of the rafter is positioned.

Right edge: The right edge of the rafter, viewed from the eaves of the selected roof surface, is positioned.

Shortening the rafters: The rafters can be shortened automatically during entry. The shortening can be applied at the upper and/or lower rafter end. If a rafter is shortened at the upper end, it automatically receives a perpendicular section. If it is shortened at the lower end, the set eaves section is retained. This makes it possible, for example, to create a blind rafter (shortened at the bottom) or the lower rafter pieces for the layer of the roof insulation.

If the option "top", "bottom" or "bottom and top" is selected here, the next appropriate fields are activated automatically.

With the additional option "from profile" the rafter setting is adopted from the profile, while the other options (top, bottom, bottom and top) override the settings from the profile.

Reference for top shortening: So that the program knows up to where the rafters should be shortened at the upper end, you can select a reference line for the upper rafter end here.

A special feature is the option "1st purlin top". With this option the program searches, starting from the top end of the rafters, for the first purlin crossed by the rafters. Ridge purlins are ignored. The rafters are cut at the first purlin found.

Distance for top shortening: In addition, a distance to the reference line for the shortening of the rafters can be entered here. A positive value shifts the cut line upward, a negative value downward.

Reference for bottom shortening: So that the program knows up to where the rafters should be shortened at the lower end, you can select a reference line for the lower rafter end here.

A special feature is the option "1st purlin bottom". With this option the program searches, starting from the lower end of the rafters, for the first purlin crossed by the rafters. Ridge purlins are ignored. The rafters are cut at the first purlin found from below.

Distance for bottom shortening: In addition, a distance to the reference line for the shortening of the rafters can be entered here. A positive value shifts the cut line upward, a negative value downward.

Consider as field boundary: With this setting you can determine whether the rafter(s) should be considered as a field boundary. This affects the splitting of a field and the filling of the roof surface with the roof assistant. If a rafter should not be considered a field boundary, the program will ignore it during a split or when filling with the roof assistant, as if it did not exist. If it is considered a boundary, it limits a field during manual splitting or splitting by the roof assistant.

Rafter nail hole: A rafter nail hole can be created in two ways. It can simply be information at the notch or it can create its own drill hole. Normally the rafter nail hole is set at the purlin and all rafters, slanted rafters, hip rafters and valley rafters that receive a notch from that purlin also receive this rafter nail hole. In some cases, however, an individual component should receive a different rafter nail hole. Then you can give that component its own setting for this. Both options have different properties:

From purlin: The rafter nail hole is taken from the purlin that creates the notch in the rafter. Depending on the setting at the purlin this can be a rafter nail hole as information at the notch or an independent rafter nail hole.

Rafter nail hole: Below this group you can choose a specific, detailed setting that then applies only to this rafter and "overrides" the setting at the purlin. If one of these options is chosen the rafter nail hole is no longer created as information at the notch but becomes an independent drill hole that is displayed as such. In addition, the rafter nail can also be generated.

Rafter connections

Rafters at eaves: For the connection of rafters to an eaves line you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Formwork notch at the eaves: A formwork notch can be created at the "eaves end" of the rafter. You can view and change the values used to generate the formwork notch with the button at the right end of the field.

Rafters with set shortening are also considered in the calculation if they would end at an eaves without shortening.

Rafters at ridge: For the connection of rafters to a ridge line you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Rafters at monopitch termination: For the connection of rafters to a monopitch roof line you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Formwork notch at monopitch termination: A formwork notch can be created at the upper end of the rafter when the rafter ends at a monopitch roof line. You can view and change the values used to generate the formwork notch with the button at the right end of the field.

Rafters at ridge purlin: For the connection of rafters to a ridge purlin you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Rafters at hip / valley rafters: For the connection of rafters to a hip or valley line you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Rafters at slanted rafters: For the connection of rafters to a slanted rafter you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

Rafters at roof kink: For the connection of rafters to a kink line you can select various treatments. You can view and change the values used to generate the respective treatment with the button at the right end of the field.

After setting all values and options you can enter the rafters using the following buttons:

Individual rafters: The rafters are placed individually. You select a point on the roof graphically. The roof surface to which the rafter should belong is determined automatically by this point. After selecting the point the positioning is queried if you have set the option "choice" for the positioning. Then you can enter a distance from the chosen point to the configured positioning edge of the rafter.

Depending on the setting, this function creates fixed rafters or additional rafters.

Split 2 pts: With the "Split 2 pts" function any area between 2 points on a roof surface can be divided with rafters. For this you select 2 points with the mouse that bound the area to be divided. The first point simultaneously determines the roof surface to which the rafters should belong. Once you have determined the field, you enter the splitting function.

Split field (field rafters): With the "Split field" function any field (= area between 2 rafters or roof skin lines) on a roof surface can be divided with rafters. For this you click with the mouse into the area of the roof surface to be divided. The program automatically searches for the rafters that bound the area. On each side where no rafter is found, the outermost roof skin line is taken as the boundary. After you confirm the field found by the program (left mouse button), you enter the splitting function.

This function always creates field rafters.