Good morning, everyone. Joining me on the call today is Mr. Humberto Nadal, our Chief Executive Officer, and Mr. Manuel Ferreyros, our Chief Financial Officer. Mr. Nadal will begin our call with an overview of the quarter, focusing primarily on our strategic outlook for the short and medium term. Mr. Ferreyros will then follow with additional commentary on our financial results. We'll then turn the call over to your questions. Please note that this call will include certain forward-looking statements. These statements relate to expectations, beliefs, projections, trends, and other matters that are not historical facts and are therefore subject to risks and uncertainties that might affect future events or results. Descriptions of these risks are set forth in the company's regulatory filings. With that, I'd now like to turn the call over to Mr. Humberto Nadal.
Thank you, Claudia. Welcome everyone to today's conference call, and thank you for joining us. This quarter, cement sales volume continued strong despite political uncertainty, proving the resiliency once again. After a very tight runoff presidential election on June 6th, yesterday, Mr. Castillo was proclaimed the next president of the country. There are claims of fraud from Keiko Fujimori and her supporters, which have brought people to the streets to protest against the way the elections were conducted. On the other hand, Mr. Castillo has shown mixed signals of moderation and radicalization, so there is still no clarity on how the next government will conduct itself. Despite this uncertainty, we are confident that cement sales will continue strong this year, mainly because our current customer base is not very dependent on macro factors.
On the one hand, the self-construction segment continues to be our most relevant source of income, and it has historically had very little correlation with high-level macro factors, at least in the short term. On the other hand, the demand coming from the public sector is basically related to the government-to-government agreement between Peru and the U.K. for re construction of the North after El Niño, and some from the government projects that were put in place to offset the effects of COVID-19. We strongly and firmly believe that neither one of these projects should be affected by a change in government, as they are well underway and are designated financing. Although sales of cement have been and continue to be the main driver of our growth, we are very pleased with the results of concrete and precast.
As we mentioned last quarter, sales of light precast materials such as precast blocks have substantially increased in the past year. Although this is more representative of our sales, we believe its performance illustrates how successful our strategy to transform ourselves and provide the construction solutions the market needs. We have generated a new customer base, mainly through the sales of precast blocks to housing projects. We believe this strategy will bring significant increase in sales volume, taking us one step closer to our long-term goals. This quarter, we are also very proud to have obtained a Silver Effie in the brand experience category for ConstruyeXperto.pe, an online platform created to redesign the homeowner's experience with training and tools that help them be very much more efficient.
As we have mentioned in previous quarters, we are convinced that our solid results in these trying times come from the fact that we have been able to reinvent ourselves to be one step ahead in terms of digitalization and of constant detection of how we can provide the best of our experience to all of our customers. This award is a clear recognition of these efforts.
Although sales are definitely important and absolutely necessary for business continuity, solid results would not be possible if we did not look at our business in an integrated manner. This quarter, we have obtained two additional recognitions that are very relevant in terms of sustainability and business continuity. First, this year, we have improved 37 positions on the Merco Talento Perú, which seeks to identify the 100 most attractive companies to work in our country.
We believe we saw significant progress, which shows our commitment to enhance human capital management, and we will strive to continue improving in this ranking every year. Finally, very importantly, this year, we have once again obtained the award for Socially Responsible Company, the ESR for its Spanish abbreviation. Although we have obtained this award every year since creation 10 years ago, for each edition, there is an evaluation of ESG parameters through specific indicators that are internationally aligned to the Global Reporting Initiative on the Sustainable Development Goals proposed by United Nations. We're particularly proud this year that we have obtained a special recognition in the ethics and integrity categories, which are very important for us.
Although 2021 is proving to be once such again a very challenging year, we have continued to deliver substantial increases in cement, concrete, and brick shipments that come as a result of our constant and permanent effort to innovate, expand our markets, satisfy new niches, and always remember to be absolutely client-focused. I will now turn the call over to Manuel for a brief analysis of financial results. Manuel?
Thank you, Humberto. Good morning, everyone. Second quarter 2021 revenues were PEN 440.9 million, a 285.7% increase when compared to the same period of last year, mainly due to the halt of operations during most of the second quarter of 2020, as well as an increased bagged cement shipment.
Even if we compare this quarter revenues to those from second quarter of 2019, there is a still significant increase of 37%. Gross profit increased substantially this quarter compared to the second quarter of 2020, mainly due to the fact that it was close to zero during the same period because of the halt in operations and the subsequent effect in gross profit, as there was no dilution of fixed costs. Consolidated EBITDA was PEN 90 million in the second quarter of 2021, representing a significant increase when compared to the second quarter of 2020, when EBITDA was negative for the above-mentioned reasons.
We expect an important increase in EBITDA for the rest of the year. During the six months of 2021, revenues increased 119% and gross profit increased 116% when compared to the same period of 2020. Mainly due to increase in sales as well as the above-mentioned halting operations from mid-March to mid-May. Turning to operating expenses, administrative expenses for the second quarter increased 41.7% compared to the second quarter of 2020, in line with increased sales. Mainly due to the substantial reduction in expenses during the lockdown period in 2020, as well as an increase in workers' profit sharing as a result of improved results. Selling expenses in the second quarter increased 71.1% compared to the second quarter of last year, mainly due to the above-mentioned decrease in expenses during 2020 and an increased profit share.
During the six months of 2021, administrative expenses increased 28% and selling expenses increased 29% when compared to the same period of last year, mainly due to the increases in sales as well as savings implemented during the six months of 2020 after the negative effect of the halting operations. Moving on to the different segments, cement, concrete, and precast sales increased 296.5% during the second quarter of 2021 compared to the same period of 2020, mainly due to the halting operations during the second quarter of 2020, as well as an increased sales of bagged cement. Gross margins increased 26.4 percentage points in the second quarter of this year compared to the same period of last year, mainly due to sustained fixed costs with virtually no selling during the second quarter of 2020.
During the six months of 2020, sales of cement, concrete, and precast increased 120.1%, and gross margin improved 5.1 percentage points, mainly due to increased sales and the halting commercialization during the second quarter of 2020. Sales of cement increased 261% in the second quarter of 2021 compared to the second quarter of 2020, mainly due to the halting commercialization during the same period of last year, as well as an increase in shipments of bagged cement as demand in the North continued booming during this quarter.
Gross margin increased 19.2 percentage points, mainly due to the negative effect on cost during the halting operation in the second quarter of 2020. During the six months of 2021, sales of cement increased 121.8% and gross margin improved 2.1 percentage points when compared to the six months of 2020, mainly due to the halt of production and commercialization mentioned above.
During the second quarter of 2021, concrete and pavement sales increased substantially since they were only PEN 3.3 million in the second quarter of last year because of the complete halting commercialization. Gross margin increased 273.5 percentage points, mainly due to the significant costs that could not be Debited on last year. Similarly, sales of concrete and pavement for the six months increased 132%, and the gross margin increased 20.2 percentage points compared to the same period of last year. During the second quarter of 2021, precast sales increased 347.4% compared to the second quarter of 2020, mainly due to halting operations. However, if we compare precast sales to the first quarter of 2021, we can see that the positive upward trend continues, since sales increased 33.3% quarter-on-quarter.
Gross margin increased 94.8 percentage points, mainly due to the negative margin during the second quarter of 2020 because of fixed costs without sales during that quarter. Similarly, during the six months, precast sales increased 31.6% and gross margin increased 20 percentage points as compared to the same period of last year. Quicklime sales in the second quarter increased 20.6% compared to the second quarter of 2020, and gross margin decreased 7.7 percentage points compared to the second quarter of 2020, mainly due to the increased demand, but most of it from granulated quicklime, which has a lower margin than ground quicklime. During the six months of 2021, sales increased 22% and gross margin increased 0.6 percentage points.
During the second quarter of 2021 and the six months of 2021, construction supply sales increased 394.2% and 161.3% compared to the same period of last year, primarily due to increase in sales from the halt in commercialization. Gross profit improved 12.4 percentage points in the second quarter of 2021 compared to the same period of last year, mainly due to a low comparative basis. In six months 2021, the gross margin remained in line with the same period of last year. In terms of debt, our debt-to-EBITDA ratio has come down to 1.9 x.
The important addition is that we have to note that we have been able to recover low indebtedness level quickly after the most trying times. To summarize this quarter's results, show the resilience in volume despite political uncertainty, and we are convinced of the financial and operational strength of our company and expect to continue delivering solid results in the upcoming quarters. Can now we please open the call to questions, operator?
Yes, thank you. Ladies and gentlemen, the floor is now open for questions. If you do have a question, please press star one on your telephone keypad at this time. If you're using a speakerphone, we ask that while posing your question, you pick up your handset to provide the best sound quality. Again, ladies and gentlemen, if you do have a question or comment, please press star one on your telephone keypad at this time. Please hold a moment while we poll for questions. Our first question today comes from Enrique Grau with Credicorp Capital. Please go ahead.
Thank you, gentlemen, for the call. I have one question. I was wondering if margins kept being affected by clinker imports. If that is the case, how much does a ton of imported clinker cost?
Yes. Of course, you have to realize that we said a year and a half ago, when we were coming to close for our full utilization of clinker capacity, it makes sense for us to import clinker till we have enough volume that makes sense to build a new plant. Even though it affects the margins, we're still going to make more money in terms of soles or dollars. The thing is, the margin will go down because imported clinker is more expensive. Regarding how much more expensive it is, normally around $20, but it all depends on the exchange rate, and it depends on the freight costs.
Okay. Can we expect these lower margins to remain for the rest of the year, and then they gradually should go up?
No. I think the first part of the year, we have used an important component of imported clinker because we had to do maintenance of our kilns in Piura and Pacasmayo. This should be at a lower rate in the second part of the year. Like I say, it all depends what happens to exchange rate and the freight rate. Yeah, margins could remain the same or could go a little bit higher.
Perfect. Thank you very much.
As a reminder, ladies and gentlemen, if you do have a question or comment, please press star one on your telephone keypad at this time. Again, that's star one if you'd like to queue up for a question or comment. Sir, there appear to be no further questions at this time. Oh, I apologize. We have one more question from Andres Soto with Santander. Please go ahead, sir.
Perfect. Good morning, Humberto, Manuel, Claudia. Thank you for the presentation. My question is, in your earnings release, you mentioned political uncertainty as some of the causes for a slowdown in volumes in the second quarter compared to the first quarter of this year. I would like to understand, what are you seeing at this point? Do you believe that now that Pedro Castillo has been confirmed as president we can expect an improvement in those projects that were sort of on standby at this point, or you expect political uncertainty to persist? If that's the case, what will you need or your clients will need to hear from Castillo's administration in order to become more constructive on Peru's political outlook?
Hello, Andres. Thank you for the question. I think I said in my opening remarks, I think our self-builders and the G2G agreements have little to do with the macroeconomic fundamentals, as they're not expecting a lot of things to be announced from President Castillo. I think they have their own dynamics. I think when we clear our daily dispatches, we are still at very strong rates, and we think we're going to for sure close this year as being a record year and the next. We think for the time being, and this is my personal interpretation, they're not so much waiting for the time. These people will keep on working the same way they kept on working through the COVID-19 crisis, and that's the strength of the informal economy, which is part of the robust economy of Peru.
Perfect. Thank you so much, Humberto.
Thank you, Andres.
Once more, if you have a question or comment, you may press star one on your telephone keypad at this time. There appear to be no further questions at this time. We'll turn the floor back to Mr. Humberto Nadal for closing remarks. Please go ahead, sir.
Thank you so much. In summary, Pacasmayo has been operating for 64 years in a wonderful, and may I stress, a wonderful and complex country. Over this period, we've had many kind of governments, going from the left, center, and right. Through it all, we have not only prevailed, but accumulated valuable experience.
We see every new chapter as an opportunity to learn and improve, and we are ready to take on the challenges that may come with the confidence in our solid fundamentals, our integrity, and our capacity to adapt will lead the way to a promising and sustainable future. We remain extremely optimistic of our company, and we will always remain very optimistic about the future of our country. Thank you very much for your interest in our company, and as always, Manuel, Claudia, and myself, we're always here in case you have any further questions.
Thank you very much. Have a very nice day, and please stay safe.
Ladies and gentlemen, this does conclude today's teleconference. We thank you again for your participation. You may disconnect your lines at this time, and have a great day.