Find out About: Knock Down vs. Welded Frames
Architects specify the type of frame for every job with openings – there isn’t a standard frame. Therefore, design professionals often have to decide which type of frame is best-suited for their project. The two types of frames and elevations are knock down (KD) and welded. This article covers the most popular types of KD and welded frame constructions, along with the pros and cons of each.
When to Specify Knock Down vs. Welded Frames
Knock Down Frames
KD Drywall Frames
Also called KD pressure-fit or slip-on drywall frames, these frames are specified for installation in existing drywall openings. They are shipped disassembled, use compression anchors, and have interlocking tabs and slots in the corners. KD drywall frames allow for assembly into the drywall opening after wall construction. Their design has visible seams and screws because they are not welded. KD frames are the least expensive because they are shipped disassembled, allowing them to be tightly packed for shipping and jobsite storage. As a general example, a truck might be able to hold 1,000 KD frames or 300 welded frames.
Standard KD Frames
Standard KD frames are specified for new wall construction. They generally have slots and tabs, but use standard anchors instead of compression anchors. Standard KD frames are assembled in the field and installed in new wall construction. Unlike KD drywall frames, they do not typically have visible screws.
Both types of KD frames are capable of meeting some fire ratings. Field welding of standard KD frames may be possible for new wall construction or existing walls at butted applications. However, field welding is usually not required and may void the fire rating, if any.
Welded frames and elevations are commonly specified for their seamless appearance and additional strength. They are particularly well-suited for exterior openings and masonry walls. Costs are higher for welded frames than KD frames. However, in addition to their superior appearance and strength, they can also achieve higher performance capabilities (fire rating, tornado, etc.) and help maintain the square and width of the opening.
Face Welded Frames
The most common type of welded frame. The joints between the head and jamb faces have a continuous weld on the visible side of both faces only. Frames are shipped assembled.
Continuously Welded Frames
Also called full profile welded or fully welded. The comer/perimeter joints have all elements of the frame member continuously welded including soffits, stops, rabbet, faces, and returns.
Face Welded vs. Continuously Welded
Continuously welded frames are the most costly due to the additional welding and hand grinding that is required. In the past, continuously welded frames were specified to provide a seamless appearance. Today, frames are mitered on precision dies and can be face welded by SDI members to provide an appearance similar to continuously welded frames. Most applications do not require continuous welding of frames and your client can achieve a high degree of aesthetics while spending less.