I will be building an 8 rise closed stair soon. The stringer will be routed out to accept the treads and risers.
The problem I have is: the right stringer (looking from the top, down) breaks to the right at a 45 degree angle for the last 4 treads. So the bottom four treads and risers are angled. Also the support of the stairs at this joint is a concern. I am not sure how to calculate the lengths of the treads and risers and where the miter cuts are made.
Anyone ever do something like this before? Any thoughts or ideas are appreciated. The builder acts like this is a normal thing. Thanks
Replies
Tack the un-routed skirt board to the wall. Lay it out full scale and make templates of the treads using 1/8 masonite, allowing for the mortice debths. Some basic math will get you close and once you see the templates in place it all becomes pretty clear.
T.C.,
Look in Amazon Tool Crib under Stair Wizard. Once you get the hang of this thing it is a dream come true. Rick
Lay out the stair on the deck full scale as a straight stair. And mark your tread increments 9, 10, 11 inches whatever they are. Now mark wher the 45-degree break starts and snap that stringer line. Now snap all your tread lines. Using the marks on the common tread to the right, snap your lines from the marks on your left common through these (right common) to the 45-degree angle stringer. This will show the shape of your treads, not counting for riser and nosing. The mortise on the breaking stinger is longer and can be calculated from here. This will give you a start I hope. Glad to help more if I can. Gotta go now.
Thanks guys. I am going to start this morning, if I did not get a response I was thinking about laying it out full scale. So thats what I will do, but things will go quicker just knowing that is the right way to go.
Spent half a day on the layout, cutting, and fitting.......heh it's my first one. Seems to have come out just fine, will put it together tomarrow morning. Thanks for the help.
The treads are being wrapped in carpet so they are particle board. I have put the mitered treads together with a double layer of biscuits (4 in each tread) and glued and screwed a 3/4" plywood (4" x 10") to the under side of the tread. I don't think that is enough support - am I being to picky or does it need more support?
Glad to hear things are progressing. I see I didn't follow you entirely this morning. So the tread is mitered where it breaks 45-degrees. If I am right by assuming that, what I suggest is snap the miter line on the floor (you probably all ready have). Now you need to invision another stringer to serve as a carriage at the miter joint. This is a traditional winder stringer. It will have the same rise but longer runs. The runs can be measured on your full scale layout. You can use two layers of 3/4 plywood laminated for your stringer board. This way it can be wide enough to give you enough arse. Be careful to avoid squeaks. Yellow glue and screws. Dadoe the treads to accept the riser and screw the riser to the back of the tread. Toe screw through the back of the riser up into the tread. the proof is in the pudding
Edited 6/24/2005 8:33 pm ET by quicksilver
In my earlier days, when I used to like to figure and calculate things in theory, I've done this.
The stringer that breaks to the right on a 45 degree can be calculated. My memory is faded because I tend to use more simple on site techniques nowadays, but simple geometry (Pythagorean) will give you the numbers.
blue
Put the stairs together and installed them without a problem. Thanks for the help to all who responded.