Peter M. Moglia
Analyst · Bank of America Merrill Lynch
Thank you, Steve. I'm going to spend the next few minutes updating you on our fourth quarter deliveries, 88 Bluxome, the Mercer Mega Block and 15 Necco progress, give an update on construction costs and then given recent activity, highlight a couple of major acquisitions that occurred in the fourth quarter and one that closed in January.
So as for developments, 2019 was a very busy year in many respects, but especially on the development and redevelopment front as we delivered over 2 million square feet at average initial yields of 7.4% on a GAAP and 6.9% on a cash basis. The fourth quarter deliveries were light relative to the first 3 quarters at 131,000 square feet, but we closed out 5 projects during the quarter and ended the year with all 11 projects spanning 9 submarkets at 95% occupancy or higher, illustrating the strong demand present in all of our markets.
Given the significant interest in 88 Bluxome in the SoMa submarket of San Francisco, the Mercer Mega Block in Seattle and 15 Necco in the Seaport area of Boston, we wanted to provide a brief update on those 3.
As many of you know, the Bay Area's team -- the Bay Area team's significant community and municipal engagement resulted in our 88 Bluxome project receiving Prop M allocation on the entire project, as opposed to approval in phases as other developers received. We are pleased to report that we are now fully entitled as all challenge periods have expired and the Central SoMa plan litigation has been resolved. We expect to receive a permit for demolition and our site work in May, and we expect to commence those activities in the summer once certain required off-site work is completed.
As you likely know, the [indiscernible] or the 1,070,000 square foot project is 46% leased to Pinterest and 58% leased overall. The status on the Mercer Mega Block is that we're negotiating a prospective purchaser consent decree with the Department of Oncology that essentially will cap our environmental liability and that should be resolved by year-end, and we should close shortly thereafter. Concurrently, we're preparing drawings for early design guidance and submittal of a master use permit shortly after closing, which will perfect the entitlement to that project. We're -- as far as 15 Necco goes, we're redesigning the building to be a lab-ready shell, and it is currently in for review with the Boston Planning and Development Agency. We expect the entitlements to be complete and have a permit to break ground in the first quarter of next year. The location has been very well received by tenants in the market, and we've had preliminary discussions with a few of them.
Moving on to construction cost. Given our proclivity for value-add activities, our underwriting process includes rigorous periodic updates of construction cost trends. The effective tariffs have been a constant theme in many of our investor meetings. And by and large, we've been able to manage through them by engaging our contractors early and leveraging our deep relationships with them to achieve the best pricing for steel and aluminum, have buyout and cover any unexpected spikes with contingency. Despite recent positive developments in the trade war, we remain cautious and conservative in our underwriting of cost as manufacturers are quick to point out, pricing is subject to change based on trade negotiations.
Our latest analysis, which we get directly from our contractors, indicates that the national average for escalations remains in the 5% range, which is consistent with 2019 and recent years. Most of our major contracting partners across our markets anticipate slowing towards the end of 2020 and into '21 and '22, which could ease pressure on pricing. Most of the pressure on pricing is attributed to skilled labor shortages. Although the construction industry continues to add jobs, most of the additions have been unskilled laborers, increasing the productivity gap, which has led to above-market pay scales for skilled workers and overtime to staff projects. The projected slowdown would mitigate this.
Moving on to acquisitions. As you know, we executed a secondary offering in January, and use of proceeds includes funding a number of strategic acquisitions. Approximately $956 million of these were completed in the fourth quarter of '19 and include the following. Arsenal on the Charles, which was disclosed at Investor Day, is located in Watertown, an inner suburb of Cambridge and closed December 17 at a purchase price of $525.5 million. This acquisition is a terrific example of our focus on value-add investments. Upon full development, we contemplate a 12-building campus, containing 1,035,000 square feet that will provide unprecedented scale in Cambridge's inner suburbs. 3825 and 3875 Fabian Way closed in December at a purchase price of $291 million and is located in the Greater Stanford submarket of Palo Alto. This 478,000 square foot campus has been leased back to the seller and provides a similarly unique opportunity for Alexandria to achieve scale on a highly valued cluster location.
The 598,000 square foot San Diego Tech Center will be rebranded as SD Tech by Alexandria and will ultimately be fully developed in phases into an approximately 1.3 million square foot life science and technology mega campus, which we own in a 50-50 joint venture. Although it's known as a premier technology campus in Sorrento Mesa, it has lost its luster in recent years and, therefore, offers us a great opportunity to leverage our redevelopment skills and long-term ownership horizon to create significant value through a thoughtful repositioning.
In addition to the 4Q '19 acquisitions, we completed 3 transactions totaling a little over $341 million in January, and I'll briefly touch on one of those as well. 275 Grove Street, also known as Riverside Center, is a 510,000 square foot office project with terrific access to Cambridge and Boston via its adjacency to the Riverside Green Line Station and location at the nexus of the Route 128 and Mass Pike Interchange. It is also located in an area of the western suburbs where a considerable amount of executive talent resides. The project is in Newton, which is within 5 miles of our Waltham Cluster, and we see this acquisition as an extension of that. In addition to the transit advantages and proximity to decision makers, Riverside Center provides optionality to incrementally convert the building to lab over time.
So with that, I'll pass the call over to Dean.