Exporting an ai file (1:10 size) to pdf (1:1 size)

I agree there is little reason to increase the file size, that is usually done at the printing step, however to answer your question, you can use Acrobat to change the size of a PDF.

Go to Tools> Print Production> Preflight Fixups (blue wrench icon), under the Pages Fixups, find, duplicate and re-name the profile Scale pages to specified size. You need to make a copy of it in order to unlock it and allow changes to the settings. After making your changes, save the new profile, With the PDF open, click on Fix at the bottom right corner and give your PDF a new name. In this example I scaled a 20 x 20" PDF to 200 x 200". You can choose either a specific destination size or percent.

Printing to PDF is a very bad plan, but fortunately it is now impossible in Mac.

Client wish or not, the PDF must be limited to 200 inches (5040 mm).

Depends on the final size ( of the wall ).  You may be able to Export > .tiff > then size up in Photoshop > Save As Photoshop PDF ( again depends on final size and appropriate resolution for output ).

PDF size limit is 5.04 Metres.

Instead of File > Save and saving the Illustrator file as PDF, choose File > Print. Select the Adobe PDF print driver and choose the Scaling setting you need.

Ingunn,

You can always change the (print) size of a PDF, so it is more of a non issue.

The crucial part is to have possible raster images at the adequate size to have an adequate resolution at 1:1, and the same applies to any raster effects; the latter means that the Effects>Raster Effects Settings setting must be 10 times (equaling the scaling factor) the adequate resolution at 1:1.

The adequate resolution of a wall project is usually surprisingly low (unless the viewer is supposed to go really close and enjoy tiny delicate details).

So it is important to have that adequate resolution established.

For general viewing, you may often judge by seeing the adequate resolution as related to the viewing angle, which means that your viewing a smaller print (or maybe even the on screen appearance) at the same angle as the final wall project may serve as an indicator to whether adequateness will be obtained.

Best to ask, of course, maybe (also) the printing company, drawing on their experience.