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Project Roundup: Week of 12/14/15

Since it's been a couple of weeks since we last posted, there are lots of projects to talk about this time. 

Zoning

One thing we've been doing more and more of is zoning plans. Whenever a property owner wants to use a building in a way that isn't normally permitted, they need to get a zoning variance. (I've written about this before: here and here.) Sometimes that's by design, where a client wants to build say, a commercial building on a lot zoned for residential use. Often, though, a property owner will be looking for a variance to "legalize" a preexisting condition on a property they just bought. Last week, I had the pleasure of visiting this beauty in the Cedar Park section of West Philadelphia in order to draw up plans to legalize a four-unit apartment building that is zoned to have only three units.

A nice twin on Springfield Avenue (we're working on the one on the right)

Historical Commission

But the fun doesn't just stop with zoning. Sometimes you want to do work on a property that's been designated as historic. In that case, anything you do to the exterior needs a sign off from the Historical Commission. We have one project that falls into that category, as well. It's a building near Logan Square that was once a single-family home, but will now be converted to luxury apartments. The windows are original, and we will have them restored to their former glory (and will take down the awful aluminum storm windows that are covering them up!). Once we have all the proper documentation together for the windows, along with the part of the back of the building that needs to be rebuilt, I can take everything to the Commission for their input.

Front elevation. This building is part of a whole row that is historically designated.

A close-up of one of those giant ground-floor windows--that trim is original!

Renovations

In renovation news, we are making progress on a nine-unit apartment building in East Germantown. This building has been underloved for some time, and its new owner really wants to make it an asset to the neighborhood. We'll be doing a full interior renovation, as well as sprucing up the exterior with new roof, windows, and a covered porch.

Existing conditions on High Street near the former Germantown High SchoolHere's a quick sketch of what we're proposing for the front. The downspout will be moved, and the metal-encased brackets around the eaves will be restored to their original condition, or removed. The large front porch will be taken over with planters on the sides and a roof in the center to provide residents with protection from the weather.

Sketch of the proposed exterior

New Construction

And as always, there's lots going on in the new-construction world. We visited Arizona Street in East Kensington to take a look at progress. We have one three-building development there which is almost complete (and all three units have sold already!). You've seen photos of that one before, but I'm happy to report that the metal panel on the front is finally complete.

Front elevation on Arizona StreetWhen you look up from the sidewalk, you get this view

We also saw our project on Coral Street (right around the corner from the Arizona Street project) get started. After a very brief period as a hole in the ground and then some concrete foundation walls, the framing is barreling ahead.

From 1) vacant lot to 2) hole in the ground to 3) foundations to 4) framing, in three weeksAnd here's a comparison of where we are today, next to the final drawing. We're doing a more traditional front than we usually do, with a nice cornice and arch-topped windows. On the side where there won't be windows, we're doing a herringbone panel that pays homage to the numerous "ghost windows" often found on factories in the neighborhood.

Today, and the future.And last but not least, we broke ground on a new residence on Tilton Street in Olde Richmond. This will be 2,700 square feet--a fairly large (for us) house--since the lot is nearly 22 feet wide. (Normally we work on lots between 14' and 17'.) It's not much to look at yet, but we'll keep updating you on its progress.

The black stuff you can see on the outside of the concrete walls is a waterproofing layerCheck back here for more updates, coming soon!

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Project Update - Mountain Street

Work has begun on an overhaul of a two-story rowhouse in South Philadelphia. The work is extensive--we've gutted the entire home, and will be rebuilding and expanding an old addition on the back. Inside, we're moving the staircase and reorganizing both floors. An old passageway from the back yard to the street (at the right in this picture) is being filled in to become additional interior space. The new plans are below:

As you can see, there will be two bedrooms and 1 1/2 baths. The basement will be for storage and mechanical systems; the laundry--usually found in the basement--has been moved to the second floor. You can see from the plans that two of the main tools I use when laying out these houses are grease and a shoehorn.

Below, you can see a before-and-after view of the rear of the house (the additional space is shown in blue). The existing house currently has a small addition that contains the kitchen on the ground floor and the bathroom on the second. This is a very typical layout (almost the only layout) for South Philly row houses. The original houses were built before indoor plumbing, so the additions were made later. In the case of this house, we'll be taking down the existing addition and rebuilding it, and it will enclose the entire width at the second floor, rather than just half.

Existing on the left, new on the right


Existing on the left, new on the right

Where the building gets slightly wider (to fill in that walkway), we'll need some new foundations. Exterior work requires extra attention to detail, to help make sure that water stays out and heat stays in. This is an example of a typical foundation detail:

Please don't copy this detail unless you really know what you're doing! This may not be the right detail for you. Contact a design professional for help with your project.

Please don't copy this detail unless you really know what you're doing! This may not be the right detail for you. Contact a design professional for help with your project.

 

The notes on the drawing help describe how to make a foundation that is strong and won't move when the ground freezes and thaws. It also shows how to keep moisture out of the basement and kitchen, how to keep the kitchen warm, and how to protect this building from a fire next door (and vice versa). It's like the little drawing that could! 

This is how the drawing was translated in the field:

The old addition hasn't been demolished yet, so what you're seeing is the new foundation next to the old walls. When the foundations are finished, the addition will be demolished and the new framing will go up.

There have already been some questions on site regarding existing conditions that were uncovered. Fortunately for my client, I was on hand to help resolve them, and we came up with cost-effective solutions that everyone's happy with.

Keep your eyes on the blog for future updates!

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Technical Tuesday: Concrete

Cooling Tower, Carling, France 1949, From the book "Twentieth Century Engineering", New York: The Museum of Modern Art, 1964.

Cooling Tower, Carling, France 1949, From the book "Twentieth Century Engineering", New York: The Museum of Modern Art, 1964.

Concrete is a part of nearly every building we build.  At the very least, its natural resistance to decay due to water makes it a part of most foundations and basements.  However, there are many misconceptions about concrete.

#1: Concrete and cement are two words for the same thing.

photos from www.quikrete.com

Cement (sometimes called Portland cement after its birthplace) is the gray, flourlike powder found in concrete.  It is made of four principal ingredients: lime, iron, silica, and alumina.  The source for these ingredients depends on where the cement is produced, but it may include limestone, marble, seashells, clay, shale, iron slag, flue dust, chalk, sand, or other minerals.  The ingredients are crushed, carefully blended, and fired in a kiln at roughly 3000° F.  The material is then crushed into the fine powder we know as cement.  Different porportions of the various ingredients produce cement with different properties.

Concrete, then, is cement mixed with aggregate and water.  Aggregate is a mixture of stone, gravel, and sand.  The size of the aggregate depends on how the concrete will be used.  The cement and water mix to form a paste that holds the aggregate together, and the finished product is called concrete.

close packing of coarse and fine aggregates

close packing of coarse and fine aggregates

#2: When you mix concrete, you just add water until it's wet enough to pour into the forms, right?

Wrong.  Mixing concrete is not like mixing salad dressing, where you can just eye it up.  It's more like baking.  The ingredients must be properly selected and carefully measured, and the proportions are very important.  For example, the proprtion of water to cement, in most cases, should be no more than 2:3.  If there is too much water, the resulting concrete will be weak and will have poor surface qualities.  If there is not enough water, the concrete will be hard to work into place.

Concrete that is too dry on the left, and too wet on the right.

#3: Once the concrete is poured, you can just leave it to dry, or, better yet, blow some fans on it to help it dry faster.

This is a common misconception about concrete.  What is happening to concrete after it is poured is not drying, it is curing.  The water and cement begin a chemical reaction, during which the cement binds to the aggregate while releasing heat.  This process starts quickly and continues for a very long time, but the concrete has reached  most of its final strength after 28 days.  During the early part of this process, it's important to actually keep the water in so that the chemical reaction can take place.  This can be achieved by covering the concrete with plastic or wet burlap, by shading it, and by protecting it from wind.  

Workmen covering a concrete panel with wet burlap and plastic to aid in proper curing.

For large surface areas like sidewalks, the concrete needs to be watered in order to keep the surface from drying out before the cement has had time to fully cure.  If it dries too quickly, the surface of the concrete will be weak, and will be subject to spalling.  Spalling happens when a weak surface layer of concrete allows water to infiltrate.  The water freezes and breaks up the surface of the concrete.

Concrete spalling on a sidewalk. Photo from www.concretesealerandblanket.org.

Hopefully this clears up some common misconceptions about concrete.  For more information, you can check out some of the many concrete-industry websites, such as http://www.concrete.com.

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