Walls and Ceilings - Unusual leaky ceiling

We have an older home with two stories. In the middle of our house is a small hallway with a ceiling that leaks during heavy rain. There is no leak though on the second floor. We've tried sealing the pipes that stick out of the roof with no luck. We can't figure out why it leaks. Help!

Welcome to the forums! It does seem there is water being infiltrated somewhere between the top and bottom floors. Water is tricky, as it will follow the course of least resistance. It could leak from the roof or guttering system, into an interior wall, run down until it touches a joist, run across the joist until it reaches the middle of the house, which could be the low point due to possible sagging, and there, drip off and cause your leak. Unless you can find where it is infiltrating the exterior, you may never be able to stop it. Sorry I couldn't be of more help, but without seeing what you see, we can't dig much further.

Findig a leak can be a challenge. It's even more challenging if you have more than one layer of roofing. Leaks around flashings are common. Check those around chimneys, in valleys, where a roof joins a wall as on an addition, skylights, vent stacks, etc. If flashings are old and rusty, it's best to replace them. Gutters and downspouts should be clear and carry water away from the structure. A stopped up gutter can send water behind the gutter where it can enter soffit and fascia. Another place where leaks often occur is around chimneys,where water can enter around masonry.

Perhaps running a water hose on the roof would be helpful in locating the leak. Always point hose downward to replicate the rain, starting at lower possible leak locations on the roof and working your way upward.

Low sloped roofs are more susceptible to wind driven rain. Flat roofs, especially where water puddles, are susceptible to leaks.

Roofing cement and caulk are only temporary fixes. They break down and deteriorate, and leaks will reoccur.

Because leak is in downstairs ceiling, do not rule out a plumbing leak or leaky wax ring at toilet. Check for plumbing leaks, too.

I know of experts who put food dye in buckets of water before sending it down suspicious areas. They will often wait for awhile to give the water a chance to make its way. By using different colored water they can quickly pinpoint where to focus...