tower TOWER (Throop Memorial Church)

David S. Lawyer

The tower structure and water leaks



3. CAULKING in 1993


5. Termites


For many decades, the tower has been a source of water leaks. It has steep stairways (ship's ladders) leading to the roof on the very top where one may enjoy a view of the city. The door to the tower staircase is located just to the S of the upstairs restroom on the same side of the hallway.


2.1 Overview

The tower has an internal reinforced concrete framework within which ordinary wood framing has been placed. The wood framing (and likely the concrete also) is covered on the exterior by tar paper, wire mesh and then Gunite (stucco). Much of the wood framing was put inside of rectangles of the concrete framework. It's held in place (from horizontal loads) by a few nails and wood wedges. These nails are driven into the concrete but often bent over showing they were not fully driven in.

The tower interior is unfinished. Tar paper, concrete and wood framing are clearly visible from the inside. The 8 buttresses one sees on the exterior of the tower are all fake and hollow. They are nothing more than bulges in the exterior tower wall (of gunite over a wood frame.

2.2 Concrete framework

The concrete is reinforced with square steel bars and also with wire (which can be seen sticking out of it). About 4 ft. above the main flat roof of the church the concrete columns make a transition in cross-section. At this point they become wider-but-thinner. At this location (in each corner) one will see a couple inches of 3/4" rebar jutting out from the upper column. This is the point where the lower column is not as wide as the upper so that part of the upper column is "supported" only by air. Into this air juts the rebar. If you look close you can also see where the rebar is cut off flush with the concrete.

2.3 Belfry

The belfry ( = bell room) of the tower has a wood floor (covered with tar paper) with a drain in the floor which apparently works. But it doesn't intercept any water which might leak down the insides of the buttresses since the floor of this room doesn't extend into the buttress cavities. The bell supports are 2@ 2"x16" (actual: 1 13/16" and 2 1/8" by 15 1/4"). There is no bell but these wood beams support the stairway. Attached to one of these beams are joists for part of a stairway landing: 2"x8" (actual: 2 3/16" x 7 5/8"). These are end nailed and should have joist hangers installed. Simpson HU36 (or HU38) hangers are 2 9/16" wide (3/8" too wide). Exact size of 2 3/16" is apparently not made. The bell on display at Neighborhood Church might be installed in the belfry (it's diameter is about 47 inches). Can it be moved into the belfry?

2.4 Top roof

The tower roof is supported by 2"x12" joists (rough, actual size close to 2"x12") on 14" centers (+- 1"). The joists on each side of the trapdoor are doubled and provide additional support for the end of the center joist. A slot for a 1" wide strap has been made on the S side between the doubled joists and the roof boards. This was used as an anchor point for webbing connected to climbing rope used for descending the tower sides.

The tower parapet walls are crenelated. There are 3 different heights on each side (2', 4.1', 6.?'). The same heights repeat resulting in 9 different segments on each side. 2': 2 @ 13-14" wide; 4.1': 4 @ 1'3"-1'4" wide; 6.?': 2 @ 3' and 1 @ 2' 9" (center). The parapet walls contain hollow tile made of red clay (terra cotta) of dimension 1'x1'x6" but are often about 1/4" smaller.

The deck that one can walk on is 16' x 16'. However the parapet walls rest on the deck also, so the full size of the deck is about 18' x 18'.

3. CAULKING in 1993

In late spring David Lawyer caulked the parapet flashings on the tower roof. He spent about 30 hours caulking cracks in the sides of the tower, making about 20 rappels down it on a mountain climbing rope using a figure 8 brake. A prussik knot was used for protection should the brake fail (it never did). This only permitted working with one hand but he was able to use his teeth as a second hand for temporarily holding the caulk gun (attached to a runner rope). It would have taken too much time to tie off the main rope since one would then need to undo the tie-off each time one needed to descend further. There are braking devices on the market which will lock which obviates the need to tie off. Liquid sandpaper does a good job of removing caulk from ones hands.

The most difficult points for starting out on a descent were the corners: One may lie on ones stomach on top of the parapet (legs on the outside of the tower) and slide down over the brink or use a second rope as protection (and direct aid) to traverse to the corner along the discontinuous ledge on the outside of the tower. I (David Lawyer) once got the safety prussik pinched between the rope and the top of the parapet and had to use emergency prussik runners I carried in my pockets to prussik upward in order to release the safety prussik. A couple of times my shirttails got caught in the brake but I never had to use the knife I carried to free myself. I also carried a whistle for use as a last resort in case I got stuck but never had to use it.

For padding to prevent the rope from fraying as it went over the brink of the parapet I used scraps of heavy vinyl linoleum. The rope still frayed a bit in other places and got contaminated by spilled caulk.

The safety harness (with the waist belt too loose) I used put most of my weight on the thigh straps which sometimes cut off leg circulation. By shifting weight from one leg to another circulation could be maintained. By tying the waist strap tighter I was able to distribute more of the weight to my waist. Also, there are some spots on the way down where one may support oneself mostly by ones feet which provided a "rest stop". I used my feet against the tower walls to position myself to each side of the plumb line of the rope. This could not have been done if I have prussiked up the rope (or gone up using Jumars). Some descents took almost an hour since there was much caulking to do on the way down. The initial exhilaration of swinging on a rope from the tower high above the street was soon replaced by the boredom of the tedious caulking work.

I found many cracks not visible from the ground and used about 15 tubes of Lexel clear caulk (the most expensive caulk available). Most tiny cracks were filled but some were not due to fatigue or running out of caulk on a descent. It is hoped they don't leak. Most of the cracks I filled probably didn't leak but since leakage depends on wind direction one cannot find all the leaks by observation of the inside during a rainstorm unless the wind blows from all directions. I used my fingers to tool the caulk into the cracks. A disadvantage of using clear caulk (not realized at the time) is that from the inside of the tower one can see light shining thru cracks that are protected by clear caulk since the light shines thru the caulk too. Someone is apt to think they see a leak unless they realize that clear caulk has been used. Another disadvantage of the clear caulk is that it is still visible many years later. After it dries is has a sheen to it which looks bad, but after a number of years this sheen goes away.

In 2001 it was noted that the clear Lexel caulk has become less clear with age. In the past, I used one tube of almond colored silicone caulk which looked no better than Lexel when first applied. Now (in 2001) it looks significantly better than the darkened Lexel. This almond caulk looked too light when first used but also may have become darker (but it's still a little too light). Caulk may get darker with age due to dust/dirt. Thus Lexel should no longer be used. I suggest using almond colored caulk in the future. Polyurethane would be best (if one can find it in almond color).


4.1 Leaks in the tower roof

The roof is at the very top of the tower. It has at crenelated parapet. Leaks and cracks have been caulked. However in Mar. 1994 the flat part of roof needed reroofing (the parapet was OK). Reroofing was done in Dec. 1995 by David Lawyer and John Miller (handyman). The flashing strips need to be kept sealed to the parapet wall. Much the water leaking from this flat roof will be intercepted by the belfry room floor drain. However, some leaking water near the exterior walls will not be intercepted by the belfry room floor. Other leaking water might (not likely) fall thru the trapdoor (nailed open) in the belfry room floor and get into the church.

4.2 Leaks in the tower sides

In Dec. 1991 a few major leaks on the E side of the tower were noted. After an early 1993 summer rain a couple more minor leaks were noted and some more caulking done. In a couple of cases water was noted at a certain location inside the tower but no crack was found nearby on the outside wall. Some of the major leaks into the buttress occurred where the buttress has a "step" which makes it wider as in goes lower. Any leak into the buttress does not get intercepted by the belfry room floor and may leak into the building

4.3 Leaks at the lower "flashing"

The flashing is where the tower walls intersect the lower flat roof (where the old skylights are). Although a contractors fixed these with tar in 1993, they cracked open a little in spring 1994 and were filled with caulk.

4.4 Leaks around the windows of the upper tower room

This is just below the bell room. This has been fixed (fall 1993) by use of flashing over the E. window and by painting and/or replacing windows.

5. Termites

In 2004 a termite inspection revealed drywood termites in the tower. They have likely been there for years. In the tower room (with the light and glass windows) termite droppings were seen in the following locations (all inside buttresses): S center, S right, E left. For the bell room, droppings were in the S center "buttress" cavity but this "buttress" is between the S louvered windows.

In May 2004, termite spray was used in locations where the termite holes had been enlarged. It's perhaps only 10% of the termite holes. Need a battery headlamp or small flashlight for applying spray.